Amusement articles possessing microbe-inhibiting properties

ABSTRACT

An amusement article for a domestic animal comprising an outer textile casing defining a shape in the form of a small article which can be carried by a domestic animal, an inner filling, and a microbe-inhibiting agent or property applied to at least one of the outer textile casing and the inner filling. The toys may be fabricated in various shapes, designs and styles, e.g., animals, bones, hearts, geometric shapes, etc. A process for applying the microbe-inhibiting agent or property to at least one of the outer textile casing and the inner filling is provided. Application methods include spraying, dipping, brushing, and rolling the microbe-inhibiting agent or property onto at least one of the outer textile casing and the inner filling.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional U.S. patent application Ser. No.09/872,500, filed Jun. 1, 2001, which is a divisional of U.S. patentapplication Ser. No. 09/059,826, filed Apr. 14, 1998, now U.S. Pat. No.6,240,879, issued Jun. 5, 2001, which claims the benefit of provisionalpatent application Ser. No. 60/043,014 filed Apr. 15, 1997, which isincorporated herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an amusement article, principally for domesticanimals, and more particularly, to an amusement article having amicrobe-inhibiting agent or property that substantially inhibits theproliferation of microbes on, within, or around the amusement article.The term “microbe” herein refers broadly to classes of bacteria,viruses, germs, molds, mildews, fungi, allergens, and othermicroorganisms. An article of the present invention provides bothcomfort and health benefits to both pets and people involved with theuse of such an article.

2. Description of the Related Art

Some conventional amusement articles for pets generally comprise atextile-based outer material and a filler material, e.g., fiberfill,foam, beads, etc. In addition, various types of noisemakers or materialssuch as catnip have also been associated with amusement articles.

The prior art amusement articles do not include a microbe-inhibitingagent or property, and therefore, do not address the problems that canarise if microbes are allowed to grow or proliferate on, within, oraround the articles. A damp environment often encourages theproliferation of microbes. Because it is common for pets, especiallydogs, to salivate upon, deposit partially digested food upon, urinateupon, or otherwise soil their amusement articles; and because sucharticles are generally porous and absorbent, microbial proliferation isespecially problematic. The fact that the articles can remain atfavorable incubation temperatures (e.g., in a dog's mouth or close to adog's body while sleeping) further aggravates the problem. Theseconditions can also make the articles attractive to other pests such asfleas and ticks. Pets using such articles, as well as their owners, canthus be exposed to an increased health hazard. The environment to whichsuch articles are exposed is unique; and the difficulty in designing anddeveloping a product which is efficacious, safe, non-toxic, andeconomical is not easy to produce. This may explain why amusementarticles for pets have not included a microbe-inhibiting agent orproperty.

Although the exteriors of pet articles can be washed, it is difficult toeffectively wash the interior stuffed or filled articles. This is due tothe difficulty of diffusing the cleaning agents into and out from thematerials which comprise the article. Organic and inorganic nutrientsfor microbes, as well as microbes themselves, often remain afterwashing. Accordingly, there is a demand in the pet products industry foramusement articles which are microbe inhibiting in nature, promote goodhygiene, are economical to manufacture, and are at the same time usablein their usual manner by the pets.

SUMMARY OF THE INVENTION

According to the invention, amusement articles for pets have aneffective amount of a microbe-inhibiting agent or property which iseffective in limiting microbial proliferation, and at the same time isnot present in quantity, concentration or nature whereby they may beharmful to the pets or humans who come into contact with the articles.The effective amount of the microbe-inhibiting agent or property limitsthe spread of the microbe-inhibiting chemicals or agents within andabout the article, takes into consideration the patterns of use andmaterial structure of the article.

According to the invention, an amusement article to be played with orretrieved by, or for enticing a domestic animal comprises a unitarypiece of non-woven material defining a shape in the form of a smallarticle for luring or being fetched by the domestic animal and aneffective amount of a microbe-inhibiting agent applied to orincorporated within at least a portion of said unitary piece ofmaterial.

Further, the non-woven material can be a fibrous batting selected fromthe group consisting of polyolefin, acrylic, nylon, polyester,polyurethane, polyethylene terephthalate, cellulose acetate, triacetateresin fibers and blends thereof.

In one embodiment, the non-woven material comprises a high loft,low-density fibrous material which is held together by bonding thefibers together. In one embodiment, the fibers are a low-temperaturecoating or sheath and the bonding takes place by heating the fibers tomelt the coating or sheath and melt-bond the fibers together.Alternatively, the fibers are adhesively bonded together.

Preferably, the article is in the form of one of an animal, a bone, aheart, and a geometric shape. In one embodiment, the unitary piece ofnon-woven material has an outer perimeter and the non-woven material issealed at the outer perimeter. The non-woven material can be sealed atthe perimeter by local heating, stitching, serging or tacking.

The microbe-inhibiting agent can be present from 0.001 to 10 percent byweight of the unitary piece of material, preferably in the range of 0.5to 10 percent by weight of the article. The microbe-inhibiting agent orproperty can be at least one of a microbe-cidal, microbe-starving andmicrobe-impenetrable agents. In one embodiment, a microbe-inhibitingagent in the form of a compound can be present in an effective amountdepending on the nature of the product.

In another embodiment, the microbe-inhibiting agent is a compoundselected from at least one of the group consisting of heavy metal salts,halogenated dioxides, quaternary ammonium compounds, halogenatedcompounds, sulfur compounds, phenyl derivatives, phenoxy derivatives,thiazoles, chlorinated phenolic compounds, polysubstituted imine saltsand phosphate esters, and mixtures thereof. Preferred compounds arechlorine dioxide, 2,4,4′-trichloro-2′-hydroxydiphenyl and the latter isincorporated into at least a portion of resin fibers which constitutethe filling or the casing. In a preferred embodiment the fillingcomprises acrylic fibers and the 2,4,4′-trichloro-2′-hydroxydiphenylcompound is incorporated into at least some of the acrylic fibers. Inanother embodiment, the microbe-inhibiting agent or property is appliedto the fibers which form either the outer casing or the filling for thearticle. In another embodiment, the microbe-inhibiting agent or propertyis bonded to at least a portion of the fibers. In a preferred embodimentof the invention, the microbe-inhibiting agent or property exhibits azone of influence which extends beyond the portion of the fibers onwhich the microbe-inhibiting agent or property is incorporated.

According to one embodiment of the invention, the amount ofmicrobe-inhibiting agent which is added to the article is computed inaccordance with the following formula:C _(B) =C _(MI) f _(MI)

wherein C_(B) is the concentration of the microbe-inhibiting agent inthe entire blend if the agent were to diffuse and become completelyhomogeneous throughout the blend. C_(MI) is the average concentration ofthe microbe-inhibiting agent within the initially microbe-inhibitingfiber and f_(MI) is the fraction of the filter blend that is composed ofinitially microbe-inhibiting fibers.

Microbe-inhibiting articles offer many advantages over the pet articlesof the prior art. One advantage is that microbe-inhibiting articlesinhibit the growth and proliferation of microbes; and, because microbialgrowth can create an environment that is attractive for many pests, sucharticles will inhibit the proliferation of pests as well.

The present invention can, therefore, provide a healthier environmentfor the pets and their “families” and, in turn, diminish the potentialfor illnesses, allergic reactions, and general discomfort. Themicrobe-inhibiting nature of the articles can also inhibit the emissionof odors. This, in conjunction with the optional incorporation of anindependent anti-odor activity into the articles, can allow the articlesto possess a pleasant or neutral scent.

The useful life of articles made in accordance with the invention isprolonged for at least two reasons. First, because the articles will becleaner and safer, one can comfortably use them for longer periods oftime. Second, because microbes and pests can contribute strongly to thephysical and chemical degradation of many materials, the articles of Atextile-based amusement article can possess inherently longer usefullifetimes.

In addition to being safer, having a more pleasant scent, and possessinglonger useful lifetimes, the articles of the present invention are moreconvenient due to fewer washings than articles of the prior art. Inaddition, by reducing the potential for undesirable microbes to enterinto the mouth of the animal, the likelihood of “bad breath” will bereduced.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a perspective view of an amusement article in accordance withthe present invention;

FIG. 2 is a cross sectional view of an amusement article in accordancewith the present invention;

FIG. 3 is a perspective view of an inner filling of an amusement articlein accordance with the present invention;

FIG. 4 is a graphical representation of X_(o) shown as a function ofC_(MI) in accordance with the design parameters of the presentinvention; and

FIG. 5 is a graphical representation of ζ shown as a function of X_(o)in accordance with the design parameters of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The term “microbe-inhibiting” in the present disclosure subsumes allcharacteristics (and the means for imparting these characteristics) thatcause a pet amusement article or toy to be inhospitable to microbes. InThe invention, distinctions are made between three types of microbeinhibition: 1) microbe-cidal, 2) microbe-starving, and 3)microbe-impenetrable.

Microbe-cidal refers to a property whereby microbes are actively killedor otherwise rendered ineffective. If a microbe comes within asufficiently close range (direct contact, for some materials; within a“zone of inhibition” for others) of a microbe-cidal material, it will bekilled or otherwise rendered ineffective. Microbe-cidal properties canbe imparted to materials by a variety of means. A preferred means usesmicrobe-cidal agents during the manufacturing process of the materialsand/or treats the materials with microbe-cidal agents. A number ofpreferred agents are disclosed below. For the microbe-cidal property tobe durable, it is often preferred that the agents be bonded in somemanner to the materials comprising the pet article. Such materialsexhibit smaller zones of inhibition than materials containing non- orweakly-bonded agents, but the microbe-cidal property with regard tomicrobes coming directly into contact with the material can be moredurable. Using agents which are insoluble or only sparingly soluble inwater can also be a key element for durability. As will be seen below,the present invention includes novel considerations involving thebonding of the microbe-cidal agents and their relations to the designsof the pet article.

Microbe-starving refers to a property whereby microbes are controlled oreliminated by deprivation of sources of nutrition. A material is saidpossess microbe-starving properties if microbes in contact with thematerial have difficulty acquiring the resources they need to survive.One can often provide or enhance a microbe-starving characteristic to amaterial by changing or altogether eliminating additives to thematerials (e.g., plasticizers, fillers, or processing aids). Becauseadhered dust or liquids can provide nutrition for microbes, it ispreferred that the material be provided with anti-adhesion properties(e.g., anti-static, low surface energy, etc.).

Microbe-impenetrable refers to the property of a material or coatingwhereby a microbe cannot pass through the material or coating. In thiscase, microbes may proliferate to some degree on a surface of thematerial, but such proliferation will be confined to the surface. Thusif an article is treated on its exterior by a microbe-impenetrablecoating, microbes from the environment will not be able to pass into theinterior of the article, will be limited in the degree to which they canproliferate, and can more readily be removed by washing. Appropriateplacement of microbe-impenetrable materials is important to theireffectiveness in providing the microbe-inhibiting property.

It is often prudent to fight the battle against microbial proliferationon several fronts. Thus, preferred microbe-inhibiting pet articles willoften possess combinations of microbe-inhibiting behavior. For example,when a particular component of a pet toy is most susceptible tomicrobial attack, this component can be treated with both amicrobe-impenetrable layer and a microbe-cidal agent, while theremainder of the article is treated with only the microbe-cidal agent.Further, an additive that serves as a resource for microbial growth maybe important only for certain parts of the article. For example,plasticizers often act as an effective resource for microbialproliferation; and one can use the plasticizer only where theflexibility is needed, and then treat this area with an effectivecombination of microbe-inhibiting characteristics; and the remainder ofthe article, where the plasticizer was not used, may be less vigorouslyprotected.

Physical cleaning can contribute to inhibiting the proliferation ofmicrobes. Organic and inorganic material can act as a barrier between amicrobe-inhibiting agent and the unwanted microbes (see, e.g., “ThePractical Application of Disinfection and Sterilization in Health CareFacilities,” by J. C. Cokendolpher and J. F. Haukos, American HospitalAssociation, Chicago, Ill., 1996). The microbe-inhibiting propertieswill therefore frequently be more potent if the article is clean. Inaddition, many organic materials can provide resources for unwantedmicrobes. Articles that possess microbe-inhibiting properties and arewashable are therefore generally preferred; and articles which are lesslikely to accumulate organic or inorganic material, due to theirstructural design or to the materials used, are also preferred.

For durability, the microbe-inhibiting agents should be insoluble orsparingly soluble in the fluids with which they come into contact. Thisincludes fluids associated with their use (saliva, urine, or otherbodily fluids) as well as washing and cleaning fluids (themicrobe-inhibiting activity should be durable to repeated homelaundering). The insolubility may be an intrinsic characteristic of theagent-fluid combination, or it may be due to the fact that the agentsare strongly bonded to the materials comprising the article. Both typesare included in the present invention.

Although both water-durable and non-water-durable microbe-inhibitingcomponents can be used with effectiveness in the present invention, if anon-water-durable microbe-inhibiting component is used, the exterior ofthe exposed material should desirably be provided with water-repellentor otherwise water-insulating qualities.

In a preferred class of embodiments, microbe-inhibiting properties areconferred upon one or more of the materials comprising the pet articleby treating the material with or otherwise incorporating into thematerial a microbe-inhibiting agent. This microbe-inhibiting agent is achemical species or particle which imparts to the material an effectivemicrobe-inhibiting property. The microbe-inhibiting agents will oftenfunction primarily through a microbe-cidal mechanism. Themicrobe-inhibiting agents are typically chemicals, polymers, solutions(solid or liquid), or particulates (which may possess their ownmicrobe-inhibiting activity or may act as hosts for othermicrobe-inhibiting agents). These microbe-inhibiting agents can exist ina variety of forms and be held in a variety of hosts before beingincorporated into the pet article. For example, they can be dissolved ina liquid; they can be incorporated in or comprise the totality of aparticulate phase, either dry or suspended in a liquid; they can beincluded within a plasticizer compound; or they can be pre-incorporatedinto a material used in manufacturing the article (e.g., one can employmaterials which already possess microbe-inhibiting properties).

A good review of chemical microbe-inhibiting agents for use in polymerscan be found in Plastics Additives and Modifiers Handbook, pp. 338-350,J. Edenbaum, Ed., Chapman and Hall, Great Britain, 1996.

The microbe-inhibiting treatment can be carried out at different pointsduring the process of manufacturing the article or its componentmaterials. For example, one can incorporate microbe-inhibiting agents inthe fibers as they are being manufactured, which microbe-inhibitingfibers can be used as the filling of stuffed toys or as the fabric usedas the external covers of stuffed toys. One can also manufacture amicrobe-inhibiting rubber-like material for use in a component of thetoy that is comprised of (e.g., molded) plastic. One can also treat (asby spraying or dipping) some or all of the materials after they arepartially or completely manufactured (e.g., one can treat the externalcover and/or the filling or some component of the filling of a stuffedtoy article before its final assembly). Alternatively or in addition,one can treat (as by spraying or dipping) the pet article when it isfinished or nearly finished in its manufacture.

Incorporation of microbe-inhibiting agents into the filler material of apet article can be performed in several ways. They can be blended withthe filling material such that the agent is dispersed throughout thepacked filler (e.g., add a liquid containing the agent to a vatcontaining the filler material). In this case, depending upon the natureof the filling material, the agent used, and the presence or absence ofother compounds (e.g., adhesion promoters, surfactants), the agent canadhere to the filler material and/or the material which confines thefiller material; or the agent can remain detached from the fillingmaterial or the confining material. The filler material can optionallybe treated with chemical agents so that the microbe-inhibiting agentsbecome complexed with all of or part of the filler.

Including the microbe-inhibiting agents within the filler materialitself (in intrafiber or intrafoam locations) generally provides greaterdurability. Intrafiber placement of the agents can be accomplished,inter alia, by known commercial fiber manufacturing techniques.

Some microbe-cidal agents must be in solution to work effectively, whileothers can be effective in a “raw” state in which they contact directlythe microbes. When durability is a dominant concern, the latter aregenerally preferred; but the former can be used to construct petarticles in which contact with liquid (as saliva or urine) activates themicrobe-cidal properties of the article.

In cases where surface attachment is desired, the use of adhesionpromoters is preferred, particularly in conjunction with “raw”microbe-inhibiting agents, i.e., those which do not need to be insolution to work effectively.

When surface attachment to the cover of an amusement article is desired,it is often preferred to use a microbe-cidal/adhesion promoter to bondthe microbe-cidal functionality to the cover. It is preferable to bondthe agent to both the outer and inner surfaces of the cover; but bondingto only one surface (preferably the outer surface) is often sufficient.

When surface attachment to the filler of an amusement article isdesired, it is often preferred to use a microbe-cidal/adhesion promoterto bond the microbe-cidal functionality to the filler.

In cases where a bonding agent is not used to attach the microbe-cidalfunctionality to the material of interest, or where such bonding is notentirely effective, it is often useful to diminish the rate at which theactive microbe-inhibiting agent becomes de-activated. This can be doneby inhibiting volatilization or adding stabilizers.

When the microbe-cidal agents are not bonded or are only weakly bondedto materials comprising the amusement article, it is preferred topackage the articles such that the effective shelf-life of theantimicrobial character is enhanced. For example, when volatilization ofthe microbe-inhibiting agent or property is a problem, the packagingmaterial can be made impervious to the volatilizing material.

It is useful to have a microbe-inhibiting agent at the surface of theamusement article, as well as in the interior. The microbe-inhibitingagent at the surface can be effective in inhibiting the proliferation ofmicrobes directly on the surface. If suitable microbe-inhibiting agentsare present in the interior, they can migrate to the surface as theagent initially at the surface becomes displaced. This processeffectively constitutes a “time-release” of microbe-inhibiting agent. Inthis manner, the concentration of the agent can be maintained at a safelevel, any odors associated with unduly high concentrations of the agentare avoided, and the period of effective microbe-inhibiting protectioncan be considerably prolonged.

The microbe-inhibiting agent can be applied in a liquid form (asdissolved in a solvent) and deposited on the surface of the cover orfiber material. By choosing properly the liquid and material, andoptionally any additives, the agent can be made to penetrate thematerial; and a “time-release” system can be obtained.

A “time-release” property can also be provided by incorporating theactive agent in a separate material, optionally particulate, whichreleases the agent in a time-controlled manner. For example, one cansaturate a particulate zeolitic material with a microbe-inhibiting agentand incorporate the zeolitic material into the pet article.Alternatively, one can use a textile chosen specifically for itstime-release characteristics for a particular microbe-inhibiting agent;and this textile can be incorporated in the article. Many other meansfor providing an effective “time-release” behavior with regard tomicrobe-inhibiting activity are possible under the present invention. Inthese cases, the microbe-inhibiting agent will generally function in amicrobe-cidal manner.

There are many ways of applying a microbe-inhibiting agent to a piece ofmaterial used in an amusement article for a pet. For example, thematerial can be dipped or passed through a bath of a slurry containingthe microbe-inhibiting agent. The material can then be passed through apair of opposed rollers which control the amount of the slurry mixtureretained by the material by controlling the pressure applied to thematerial as it is passed between the rollers. Upon leaving the squeezerollers, the material is dried in a process oven. After drying, thematerial can be further processed by being coiled into rolls and/or cutinto the final desired shape and size.

If some form of heat-assisted disinfection of the articles is desired,it is important to use material-agent systems which do not degrade inthe disinfection environment (e.g., dishwashers, microwave ovens,conventional ovens, etc.). The softening or decomposition temperaturesof the polymers and chemical agents used, for example, must be higherthan the disinfection temperature used.

Because the accumulation of undesired organic or inorganic matter mayreduce the efficacy of microbe-inhibiting protection, the articles canbe designed with materials that reduce the tendency for suchaccumulation. This result can be accomplished by using low surfaceenergy materials or applying a low surface energy coating; and/or byusing anti-static materials or applying an anti-static coating.Non-hydrophilic materials (materials upon which water droplets formcontact angles greater than about 30 degrees) are generally preferred toprevent the adhesion of such undesired matter.

It is often preferred to provide some surfaces of the pet article withboth microbe-cidal and anti-adhesion properties. Thus, organic orinorganic matter is less likely to become attached to the article; ifsuch matter does become attached, it is more easily removed; microbesare less likely to attach to or penetrate into the article; and microbesthat remain in contact with the surfaces can be eradicated by themicrobe-cidal properties of the surfaces. A preferred means of obtainingsuch a surface is to treat the surface with a combination of amicrobe-cidal agent and a low surface energy agent (e.g., a groupcontaining a fluorinated functionality). Both of these agents can beprovided with an adhesion promoter functionality as well.

The anti-stick efficiency can be increased by including an anti-staticagent, preferably an anti-static agent that can be bonded using anadhesion promoter, as a silane coupling agent.

Pets, especially dogs, often tear or otherwise damage the amusementarticles that they use; and they sometimes eat the articles or theircomponents. It is therefore important that the materials are non-toxicand non-carcinogenic at the levels used in the articles. Some agents arenon-toxic even at relatively high concentrations (e.g., Triclosan,stabilized chlorine dioxide); other agents are non-toxic at relativelylow concentrations, but become toxic at high concentrations (e.g., manyunbonded quaternary ammonium compounds). If a pet article employs a timerelease property, one must ensure that the time-releasing materials donot contain concentrations of the agents that exceed that can be safelyeaten by the animal of interest. Essentially, the pet should be able toeat the article without harm. Also, the treated materials should benon-skin-sensitizing, i.e., should not generally cause allergic or otherundesirable reactions on the skin or other membranes of the pet orpeople who effectively come into contact with the materials.

For safety, durability, microbe-inhibiting efficacy, and ease of use,phenol derivatives, especially 2,4,4′-trichloro-2′-hydroxydiphenol(sometimes known, among other names, as Triclosan, Irgasan, or Microban)incorporated into the constituent materials (e.g., fibers or foam) atthe time of manufacture of such materials are particularly preferred.This provides most readily for the microbe-inhibiting agent to become anintegral part of the material. These agents in particular can be readilyincorporated in the manufacturing processes for the constituentmaterials; they are generally non-toxic and non-carcinogenic (even atrelatively high levels); they generally do not cause adverse skinreactions; they tend to migrate from the bulk of the material to itssurface when they are depleted from the surface; and they are veryefficacious in inhibiting the proliferation of a wide variety ofmicrobes.

Referring now to the drawings and to FIG. 1 in particular, a firstembodiment of an amusement article 10 is shown as having a bear-likeperipheral geometry. The amusement article 10 preferably weighs less 250grams. While the amusement article 10 has been shown, for illustrativepurposes only, as substantially bear-like any one of a number ofperiphal geometries are likewise contemplated for use including, but byno means limited to a human, ball, bone, lion, duck, bunny, cow, pig,lamb, dinosaur, monkey, elephant, koala, leopard, tiger, fish, footbal,penguin, and a whale. The only limitation with regard to the peripheralgeometry of the amusement article 10 is that it must be configured suchthat an ordinary domestic animal can carry the article.

As shown in FIG. 2, the amusement article 10 generally comprises anouter casing 12, an inner filling 14, and an microbe-inhibiting agent orproperty 16. The outer casing 12 can be fabricated from woven,non-woven, knitted, and nylon fabrics. Preferably the outer textilecasing 12 is fabricated from a woven or knit fabric comprising a highpile component 18 that is attached to a backing material 20 and, inturn, forms an artificial fleece. In one embodiment, the outer textilecasing 12 is made from a tightly woven fabric. Other material, such asrope, rubber balls, hard plastic components, etc., can be combined withthe fiber-based outer casing to make a toy more attractive to a domesticpet. Other components can be included, e.g., to impart flame resistanceto the amusement article 10. Modacrylic polymers of particular utilityin the present context are those comprising acrylonitrile, vinylidenechloride, and/or vinyl bromide units.

The inner filling 14 can be fabricated from a fibrous filling, foam, orbeads. Preferably the fibrous filling is fabricated from polyolefin,acrlyic, nylon, polyester, polyurethane, polyethylene terephthalate,cellusoe acetate, and triaceate resin fibers. Mixtures of any and/or allof the resin fibers are likewise suitable for use in the amusementarticle 10. When beads are used as the inner filling a mesh bag can beused to retain the beads in the event that the outer casing would open.While the beads can be fabricated from any one of a number ofcompositions, polystyrene is the preferred composition due to, amongother things, cost and weight factors.

When the inner filler 14 is fabricated from polyolefin resins,polyethylene and polypropylene are preferable—especially low-densitypolyethylene resins such as Dow Chemical's “LDPE 640.”

When acrylic polymers are used as the inner filler 14, acrylonitrileunits and either vinyl acetate, methacrylate or methyl methacrylateunits are preferred.

The inner filling 14 can also be fabricated from foam, due to their easeof manufacture and their low cost on a volume basis. Foam materials canbe cut to the desired shape and then employed as a filler within a petarticle; they can also serve as the article itself, or the foam can beformed within a cover material for the article. If a cover material isused, it is preferred to form a contained structure with the covermaterial (effectively a shaped “bag”) and then to inject microbe-cidalfoam precursors through an aperture in the structure and foam in place.The aperture can then be sealed.

Various materials in sheet form can be useful in the construction ofmicrobe-inhibiting amusement articles for pets, either as the cover orcontainment structure of the article or as a microbe-inhibiting liningthat can be incorporated into a conventional pet article to providemicrobe-inhibiting properties. For example, one can attach such amaterial to the inner side of the cover of a stuffed pet toy. In usingsuch linings, it is generally preferred to employ materials with lowpermeability (e.g., microbe-inhibiting vinyl sheets); but when sewing isnecessary, conventional fabrics (e.g., microbe-cidally treated cotton orpoly/cotton blends) are preferred for ease of manufacturing of thearticle.

The design of an attractive microbe-inhibiting article for pets involvesa unique balance of considerations with regard to material selection.The demands placed on the efficacy of the microbe-inhibiting agents usedare lessened by using materials that are naturally less inclined toharbor microbial proliferation. The natural microbial resistance ofmaterials derived from cotton, flax (linen), and rayon fibers areparticularly poor. Materials derived from acrylic, polyester, nylon,olefin, triacetate, rubber, and spandex fibers possess much betternatural microbial resistance.

Because microbial proliferation usually requires the presence ofmoisture, it is additionally attractive that the constituent materialsdo not readily take-up or absorb/adsorb water. The degree to whichfibers do take-up or absorb/adsorb water is a function of the surfaceproperties and the microstructure (e.g., porosity). One is generallyinterested in fibers that are poorly wetted by water and display a lowmoisture regain. Polyester and acrylic are two of the most useful,commercially available fibers in this regard. Because they both alsopossess good natural microbial resistance and readily take-upmicrobe-inhibiting chemicals, they are preferred materials from which toconstruct microbe-inhibiting amusement articles for pets.

Nylon possesses good natural microbial resistance, and is thusattractive for use. Acetate possesses only moderate natural microbialprotection (triacetate is better); and if used to a significant extent,it should be incorporated with a microbe-inhibiting agent.

Another consideration which is relevant for dog toys relates to theobservation that dogs often prefer toys that pick up their scents; andthis is encouraged on toys that can absorb or otherwise take up some ofthe dog's saliva. It is therefore sometimes advantageous to include somefraction of material that is hydrophilic or at least not stronglyhydrophobic, and which displays a moderate moisture regain. For example,one can include a fraction of cotton or acetate (or triacetete) fiber.

A preferred article is thus manufactured using materials derived fromacrylic, polyester, and/or nylon fibers; and smaller parts of cottonand/or acetate (or triacetate) fibers can be incorporated advantageouslyas well. Some fraction of these materials in the preferred article areincorporated with microbe-inhibiting agents such as2,4,4′-trichloro-2′-hydroxydiphenol (e.g., Triclosan) at the time ofmanufacture of the constituent fibers.

Selection of Plasticizer

Although some polymers possess a significant degree of naturalinhospitableness to microbial proliferation, they can lose thisdesirable property if they are processed using certain plasticizers. Theplasticizers used in processing many polymers are digestible and/ordegradable by microbes. If a plasticizer is to be used in processingmaterials used for constructing an amusement article for a pet, it ispreferred to chose a plasticizer that does not diminish the naturalmicrobe-inhibiting property of the polymer. Listed below areplasticizers that are resistant to fungal growth: Abietic acid; hydrog.methyl abietate; tri-n-butyl aconitate; triethyl aconitate;di-(2-ethylhexyl)adipate; di-(2-ethylhexyl)acetate; ethyl-o-benzylbenzoate; chlorinated diphenyls; chlorinated paraffins; tri-n-butylcitrate; triethyl citrate; 2-nitro-2 methyl-1,3-propanediol diacetate;dimethyl phthalate; di-n-propyl phthalate; diisopropyl phthalate;dibutyl phthalate; diisobutyl phthalate; diisodecyl phthalate; dihexylphthalate; dicapryl phthalate; di-(2 ethylhexel) phthalate; di-(2ethylhexyl) phthalate; dicyclohexyl phthalate; dicyclohexyl phthalate;and dibenzyl phthalate.

Non-Wovens

Some articles of The invention can be made in whole or in part fromnon-woven fabrics. These are generally made from extruded continuousfilaments or from fiber webs or batts strengthened by some form ofbonding between or among fibers. The fibers can be bonded, e.g., byheating (including use of low-melting coatings), by adhesives,stitch-bonding or mechanical interlocking (e.g., needling).

A preferred base material is often polyester or olefin fibers orfilaments; and preferred non-woven for the present invention is a veryhigh-loft, low density type such as those used in filtration systems.These non-wovens can be prepared at large thickness (on the order ofinches) and die-cut into toy shapes.

More traditional non-woven fabrics (e.g., non-woven felt) can be used ascover materials in articles of the present invention.

In preparing microbe-inhibiting fibers, the microbe-inhibiting agentscan be incorporated in a variety of ways, including adding themicrobe-inhibiting agents to the melt or the spin dope from which thefibers are spun; or impregnating or otherwise treating the filaments asthey are being stretched, washed, dried, cooled, solidified, orotherwise treated. One can also treat finished fibers by soaking orspraying in a solution containing a microbe-inhibiting agent.

When synthetic fibers are being used, it is preferred to add themicrobe-inhibiting agents to the melt or the spin dope from which thefibers are spun (extruded). In this case the microbe-inhibiting agentbecomes an integral part of the fiber; and the durability of theresulting microbe-inhibiting efficacy is generally enhancedconsiderably. Phenol derivatives, especially2,4,4′-trichloro-2′-hydroxydiphenol (sometimes known as Triclosan,Irgasan, Microban, or by other names) are particularly attractive.Organotins, especially Tri-n-butyltin maleate (as in Ultra Fresh DM-50),are also attractive.

In the case of fibers that are melt spun, it is important to ensure thatthe degradation temperature of the microbe-inhibiting agent is higherthan the melt temperature. Because of the lower temperatures used,solution spinning methods are generally preferred for the manufacture ofmicrobe-inhibiting fibers.

If the microbe-inhibiting agent is to be incorporated into a preformedfiber or tow, it is often preferred to do so when the fiber stillpossesses an open and/or porous structure. This particularly beneficialwhen solution-spinning acrylic or modacrylic fibers, where themicrobe-inhibiting agent can be applied to the filaments from the finishbath through which the filaments pass en route to the drying rolls. Whenthe filaments are then processed on the drying rolls, themicrobe-inhibiting agent is retained in the fiber. After themicrobe-inhibiting agent is applied to the tow, care must be taken sothat the microbe-inhibiting agents are not volatilized during subsequentprocessing.

In the case of melt-spun fibers, the microbe-inhibiting agents can beapplied to the filaments either prior to or along with the spin finishapplication. When applied prior to the spin finish application, themicrobe-inhibiting agents are preferably applied from an aqueoussolution or emulsion thereof. A spin finish-containing agent can beapplied to the filaments in a conventional manner, e.g., by passing thefilaments over a metered finish applicator where a predetermined amountof finish is applied to the filaments.

Fiber to be used as fiberfill can also be treated so as to possessmicrobe-inhibiting properties at the time it is incorporated into thecontainment structure by a blowing/filling machine. The blowing/fillingmachine can be constructed so as to spray, soak, or otherwise contactthe fiber with the appropriate microbe-inhibiting treatment solution.For this application, Tri-n-butyltin maleate (Ultra Fresh DM-50) is apreferred agent.

It is important to note that post-treatment methods involve importantlydifferent considerations when one is using a “strongly-bonded” type ofagent. In the “diffusing” or “non-strongly-bonded” case, one immerses orotherwise exposes the materials to a solution containing a particularconcentration of the agent. Generally, the agent diffuses into thematerial until its concentration in the material is comparable to theconcentration in the solution, i.e., the treatment level of the materialis essentially proportional to the concentration of the agent insolution; and the agent concentration in the solution is the primarycontrolling variable. In typical treatments, the agent in solution isnot appreciably depleted; and the amount of material exposed to thetreatment solution is not carefully monitored and is not considered aprimary variable of the treatment process.

In the strongly-bonded case, however, the agent usually does not diffuseinto the material (fiber, fabric, etc.); rather, it chemically reactswith the surface of the material. Here one attempts to arrangeconditions such that most of the “reactable” agent present in thesolution reacts with and bonds to the surface of the material beingtreated. Knowledge of the amount of material being treated is thusimportant in determining the treatment level; and the material amount,along with the agent concentration in solution, are consideredcontrolling variables of the treatment.

As used herein, the “amount of material,” means the “amount of reactablesurface” of the material. For porous materials that can take up thesolvent in their interiors (e.g., many fibers or fabrics), the mass ofthe material is often used as an indicator of the reactable surfacearea—i.e., one can specify an agent level in solution per unit weight ofmaterial being treated. For non-porous materials and/or materials whichdo not absorb the solvent being used (hard plastics, highlysolvent-phobic materials), more direct knowledge of the reactablesurface area is needed.

The length of the cut fiber figures importantly in the blending process.It the fibers are too long, blending can be ineffective. If themicrobe-inhibiting fiber is not homogeneously blended, themicrobe-inhibiting resulting efficacy of the resulting amusement articlecan be dramatically reduced. Filling using a blowing/filling machine canalso become problematic with longer fibers (if the fibers are very long,hand filling can also be considerably more difficult). For articles ofthe present invention, the cut length of the fiber should be between 0.1and 8 inches, preferably between 0.3 and 5 inches, and most preferablybetween 0.4 and 3.5 inches.

When fiber blends are used, it is preferred that both themicrobe-inhibiting fiber and the non-microbe-inhibiting fiber bothpossess the same cut length.

Microbe-inhibiting fabrics may be constructed by weaving, knitting, orotherwise forming the fabric from fibers which possess the desiredmicrobe-inhibiting properties. Alternatively, the fabrics can be posttreated via spray-treating or by using a padding system such as arecommon in the art of textile finishing. For post treatment,Tri-n-butyltin maleate (as in Ultra Fresh DM-50) is a preferreddiffusing microbe-inhibiting agent (at fabric pick-up about 0.1%-0.5%);and 3-trimethoxysilylpropyldimethyloctadecyl ammonium chloride (as inDow Corning 5700) is a preferred strongly bonded microbe-inhibitingagent (at fabric pick-up about 0.08%-0.15%).

The preferred means for obtaining microbe-inhibiting foams is to includea microbe-inhibiting agent in the formulation of one of the foamprecursors (i.e., before the material is foamed) A preferredmicrobe-inhibiting foam is obtained by adding Ultra Fresh DM-50 to thepolyurethane foam formulation before foaming (typically in amountsranging from 0.04% to 0.6% relative to the total weight of theformulation). Another preferred means is to use Dow Corning 5701 (areactive silane quaternary ammonium compound, which works much like DowCorning 5700). This agent is also added into the formulation of the foambefore foaming (typically in amounts ranging from 0.1% to 1.2% relativeto the amount of polyol).

It would be a further benefit to articles of the present invention thatthey resist the proliferation of mites, fleas, ticks, and other pests.One means for inhibiting the ability of such pests to proliferate in theinterior of the articles of the present invention is to use outerfabrics possessing very tight weaves (so the pests cannot pass throughthe interstices or pores of the fabric. Another means, particularlyefficacious for inhibiting the proliferation of dust mites, is to usethe microbe-inhibiting agent Ultra Fresh DM-50 in treating or preparingthe fabric, foam, fiber and/or other materials used in the article (thisagent appears to possess the ability to limit dust mites).

Microbe-Inhibiting Agents

A wide variety of chemicals can be used as microbe-inhibiting agents inthe present invention. For listings of chemical additives which canimpart anti-microbial properties, see the Plastics Additives andModifiers Handbook (pp. 338-350, J. Edenbaum, Ed., Chapman and Hall,Great Britain, 1996); Plastics Handbook (Modern Plastics, 1994, McGrawHill); and The Practical Application of Disinfection and Sterilizationin Health Care Facilities (J. C. Cokendolpher and J. F. Haukos, AmericanHospital Association, Chicago, Ill., 1996).

Nearly all heavy metals possess some degree of microbe-inhibitingactivity (especially of the anti-fungal kind). Copper naphthenate, e.g.,can be applied from a solvent bath, optionally with additionalmicrobe-inhibiting agents in the same bath. Alternatively, fabric orfill can be impregnated with a copper salt dissolved in ammonia, andthen treated with napththenic acid. Other useful copper salts includehydroxynaphthenate, stearate, tallate, oleate, resinate, acrylate,furoate, antimonate, and chloracetate.

Chlorine dioxide, typically in aqueous solution, also possessesmicrobe-inhibiting properties, and it can be used to impart suchproperties to amusement articles for pets. The articles can be soaked inthe solution or can be treated topically with the solution, orconstituents of the articles can be treated with the solution. Chlorinedioxide is attractive because it can be obtained in a stabilized form inwhich it is non-toxic. It is used in toothpaste and mouthwash forhumans, and it is a particularly preferred microbe-inhibiting agent orproperty for the invention.

The microbe-inhibiting properties of quaternary ammonium compounds arewell known; and several examples are given below. They can be used aloneor in conjunction with other microbe-inhibiting agents, preferably inconjunction with adhesion promoters, especially alkoxysilane couplingagents. A preferred example is Dow Corning 5700 microbe-inhibiting agent(3-trimethoxysilylpropyldimethyloctadecyl ammonium chloride). Additionalagents suitable for use in this context include cetylbenzyldimethylammonium chloride, tertiary octylphenoxyethoxyethylbenztyldimethylammonium chloride, and lauryl pyridinium chloride.

Suitable other quaternary ammonium compounds include polyamniopropylbiguanide, 1-(3-chlorallyl)-3,5,7-triaza-1-azoniaadamantane chloride(available under the trade name Dowicil 200 from Dow Chemical). Stillother suitable quaternary ammonium compounds are included in the nextsection.

Effective organic sulfur compounds include the microbe-inhibitingorganic preservatives containing 3-isothiazolone groups and sodiumpyrithone. Halogenated compounds suitable for use in the present contextinclude 5-bromo-5-nitro-1,3-dioxane (available from Henkel under thetrade name, Bronidox); 2-bromo-2-nitropropane-1,3-diol (available fromInolex under the trade name, Bronopol); 1,1′-hexamethylene bis5-(p-chlorophenyl) biguanide (commonly known as chlorohexidine) and itssalts; 1,1,1-trichloro-2-methylpropan-2-ol (commonly known aschlorobutanol); 4,4′-(trimethylenedioxy) bis-(3 bromobenzamidine)diidethionate or dibromopropamidine. The addition of thiazolederivatives, specifically 2-mercaptobenzothiazole, is useful. Thiazolescan be used effectively in mixed combination with other chemicals suchas the quaternary ammonium salts and selected metal derivatives, e.g.,of mercaptobenzothiazole, in which the metal itself possessesantimicrobial properties.

Suitable phenyl and phenoxy compounds include4,4′-diamidino-alpha,omega-diphenoxypropane diisethionate (commonlyknown as propamidine isethionate); and 4,4′diamidino-alpha,omega-diphenoxyhexane diisethionate (commonly known ashexamidine isethionate. Other examples are benzyl alcohol2-phenylethanol, and 2-phenoxyethanol.

Chlorinated phenolic compounds are generally preferred for incorporationinto the bulk of many materials. 2,4,4′-trichloro-2′-hydroxydiphenol isespecially attractive and, for reasons discussed herein, is a highlypreferred agent in the present invention. Other possible chemical namesfor this agent are chloro-2-(2,4-dichlorophenoxy)phenol;5-chloro-2-(2,4-dichlorophenoxy)phenol; or2,4,4′-trichloro-2′-hydroxydiphenyl ether. Trade or common names whichare comprised primarily of the agent are Triclosan, Irgasan, IrgasanDP-300, Microban, Microban B, Lexol 300, and others. The Ultra Freshfamily of agents, solutions, and materials, available from ThomsonResearch Associates, often include significant amounts of thistriclosan-type additive (sometimes, along with quaternary ammoniumcompounds and/or tributyltin oxide compounds).

DM-50 (Thomson Research Associates) is a preferred form of the preferredorganotin agent, tri-n-butyltin maleate.

Another preferable microbe-inhibiting agent is known by the trade nameIntersept. It is a complex of polysubstituted imine salts and trialkylphosphate esters with free alkylated phosphoric acid. It is relativelynon-toxic and has been used as an antimicrobial finish on many buildingmaterials.

A further preferred type of microbe-inhibiting agent is typified by theMicroFree brand of particulates (available from DuPont). Theseparticulates generally comprise a core particle (zinc oxide, titaniumoxide, or barium sulfate) over which is coated a microbe-inhibitingactive layer (silver, copper oxide, and/or zinc silicate). A barrierlayer (to control the rate of release of the active component) and adispersion coating (to facilitate dispersion of the particles in hostmaterials) are included on top of the active layer. The particles rangefrom about 0.3 μm to 1 μm in size. They can be incorporated into manyresin systems for plastics processing, into the dope before fiberspinning, and into many coating systems for post-treatment. Goodmicrobe-inhibiting efficacy can be imparted to various materials usingthese particles, and the resulting materials are generally non-toxic,very stable, and cost effective.

The microbe-inhibiting agent chosen depends on many factors includingtoxicity, the desired method of incorporation, material compatibilityissues, and economic considerations.

Lists of Compounds and Solutions with Selected Concentrations

Below is a listing of chemical compounds with demonstrated effectivenessfor various microbe-inhibiting applications. The effectiveness of eachdepends upon its concentration, the presence and concentrations of othermicrobe-inhibiting agents, the nature of the surface, the temperature,the overall pH of the solution, etc.

Most of the microbe-cidal chemicals listed are followed by arepresentative effective concentration range. These concentration rangesare meant to be typical and representative; the concentration actuallyused can vary with other conditions of the treatment, with the nature ofthe host material, with the concentrations and efficacies of othermicrobe-cidal agents (or microbe-starving or microbe-inhibitingproperties) present, and with the degree of toxicity allowable.

As used herein, all concentrations given in units of percent areunderstood to be weight percent (unless otherwise stated).

Chemical Compounds Commonly Used as Additives in Polymers

The agents listed in this section can be used as additives in polymers,but many can also be used effectively in liquid treatment solutions. Thepreferred concentrations depend on a variety of factors, including thetype of polymer, its required physical and chemical properties, thedegree of toxicity allowable, and the environment in which the petarticle is to be used.

Unless otherwise stated, when concentrations are given below, theycorrespond to the percentage of the total plastic or liquid formulationthat is the microbe-inhibiting agent. In some cases, a preferredmaterial is given with which the additive is compatible and effective.The chemical compounds (and in some cases broad categories of compounds)and typical concentrations are as follows:

Copper-8-quinolinolate (0.2-4%, in, e.g., vinyl); mercaptan (0.2-4%, in,e.g., vinyl); tetramethylthiuram disulfide (0.4-4%, in, e.g., vinyl orcellulose nitrate); copper napthenate (0.2-4% in, e.g., PVC or PVA);pentachlorophenol (1-20%, in, e.g., lacquer or cellulose nitrate);phenyl mercuric formate (0.05-10%, in, e.g., nylon); pentachlorophenol(0.2-4%, in, e.g., celluose nitrate); 10,10′-oxybisphenoxarsine (OBPA)(0.005-2%, in a variety of plastics, including vinyl, PVC, and others;sometime sold under trade names, “Intercide” or Vinyzene); organotins(0.005-2%, in, e.g., PVC) (examples of organotins are, e.g., bis(tri-n-butyltin)sulfosalicylate (0.25-0.5% of plasticizer, used in e.g.,PVC), or the preferred tri-n-butyltin maleate (0.005-1%, in, e.g.,urethanes, paint-compounds); brominated salicylanilide (0.04-1%, in,e.g., polyethylene).

Phenolic species, particularly especially chlorinated phenolics(hexachlorophene, dichlorophene, p-chlorometacresol,p-chlorometaxylenol, o-benzyl parachlorophenol, and o-phenylphenol), andespecially 2,4,4′-trichloro-2′-hydroxydiphenol (0.05-10%)—the latter hasbeen incorporated successfully into a number of plastics and otherproducts; it can be written as is 2,4,4′-trichloro-2′-hydroxydiphenol,or as 5-Chloro-2-(2,4-dichlorophenoxy) phenol; and may be referred underthe names Triclosan, Irgasan, Microban, Microban B, Lexol 300;quarternary ammonium compounds (e.g., quarternary ammonium napthenate(0.5-6% of the plasticizer, used, e.g., in PVC); blends of substitutedammonium salts of alkylated phosphoric acids mixed with a free alkylatedphosphoric acid (especially complexes of polysubstituted imine salts andtrialkyl phosphate esters with free alkylated phosphoric acid)—0.1-4% ofthe coating used; Fungitrol 11 (N-trichloromethylthiopthalimide powder);Vancide 89 (N-(trichloromethylthio)-4-cyclohexene-1,2-dicarboximide,powder); Microchek 11 (2-N-octyl-4-isothiazlin-3-one, liquid); Omacide(zinc pyrithione); Preventol (N-(fluorodichloromethylthio)pthalamide);Apacider (silver hydroxyapatite); and Vinyzene SB-129 contains as anactive ingredient N-(2-Methyl-1-naphthyl)maleimide.

Design of Microbe-Inhibiting Amusement Articles for Pets

Some microbe-inhibiting materials contain an agent which can diffuse outof the material. Such materials generally exhibit a significant “zone ofinhibition,” whereby microbial growth is effectively inhibited somedistance away from the material (e.g., see Plastics Additives andModifiers Handbook, pp. 338-350). In these materials, the agent is notfully bonded to or otherwise trapped in the material, and it can betransported from the material into its surroundings. FIG. 3 demonstratesthe zone-of-inhibition, shown in dashed lines 36, as surrounding themicrobe-inhibiting fibers 34, and encompassing regions containing theinitially non-microbe-inhibiting fibers 32.

In other cases, the microbe-inhibiting agents may be strongly bonded toor otherwise trapped within the host material. The zone of inhibition isvery small for these materials; and microbes are killed or otherwiseinhibited only by coming into direct contact with the material.

The behavior of the zone-of-inhibition 36 affects the design ofefficacious microbe-inhibiting amusement articles for pets. For example,if the fiber used as the filling of a stuffed pet article has beenprovided with a strongly bonded microbe-inhibiting agent, then the zoneof inhibition is very small; and the filling should be composed almostexclusively of the microbe-inhibiting fiber. In addition, themicrobe-inhibiting fiber will not spread its microbe-inhibiting efficacyto the cover; and if any protection is desired on the cover, it must beseparately supplied.

If the fiber is provided with a diffusing microbe-inhibiting agent,however, the design is more complicated. It is preferred to use a fiberblend in which only a modest fraction of the fiber is provided withmicrobe-inhibiting properties. Over time, and accelerated by use, theagent will diffuse to the fibers which were not initially provided withmicrobe-inhibiting properties. In addition, if the agent is suitablymobile, it can impart a microbe-inhibiting characteristic to the coveras well. In this case, one must properly consider the interplay betweenthe characteristics of the zone of inhibition (its extent, shape, decaycharacteristics, and dependence on the surrounding fiber packingdensity), the rate of depletion of the microbe-inhibiting agent from thefiber (and how this impacts the characteristics of the zone ofinhibition), and the distribution of the microbe-inhibiting fiber withinthe total filler.

If the agents are extremely mobile and weakly attached to the hostmaterial, they will readily and rapidly diffuse to contiguous materialsthat contain smaller concentrations of the agents; and this will occuruntil the overall concentration approaches uniformity. In this instance,as long as there is extensive contact among the fibers comprising thefiller, the zone of inhibition is essentially limitless in extent; and,for the pet article to be provided with microbe-inhibiting properties,one must only ensure that there is enough agent present in the fibersthat initially contain the microbe-inhibiting agent that the overallconcentration will remain at a sufficient microbe-inhibiting level forthe desired lifetime of the article. Thus, the important parameter indesigning articles in this case is the total concentration of themicrobe-inhibiting agent. Issues related to the design of yarns andfabrics under these conditions are discussed in U.S. Pat. Nos. 3,959,556and 4,842,932.

The prior art, however, provides no teaching for the case in which aneffectively finite zone of inhibition is exhibited by themicrobe-inhibiting fiber, nor for the case in which themicrobe-inhibiting material is particulate in nature, nor for the casein which the fibers comprise the filling portion of a containmentstructure (rather than the filaments of a yarn or of a fabric).Teachings for these cases are provided below.

An important distinction between fiber as used as filling in the presentinvention, as opposed to fiber as used in yarns and fabrics of the priorart, is that the fiber used as filling in the invention is typically thecomponent of the interior of a containment structure within which thegreat majority of the space (by volume) is typically comprised by air.

As mentioned above, the prior art deals with cases in which thediffusing microbe-inhibiting agent easily leaves its initial host andpermeates the entire space of the yarn or fabric of which it is part(i.e., an effectively infinite zone-of-inhibition). In systems of thisinvention, however, there are typically restrictions on the transport ofthe microbe-inhibiting agents and/or the agents possess a significantdegree of attachment to their hosts; and a finite zone-of-inhibition ispresent. In this case, for adequate microbe-inhibiting protection, onemust ensure at the very least that that the microbe-inhibiting fibersand their associated zones of inhibition comprise a sufficient volumefraction of the containment volume.

Designing Pet Amusement Articles Having an Microbe-Inhibiting Agent orProperty

In the invention, there are two basic approaches to the design ofeffective microbe-inhibiting pet amusement articles: 1) an empiricalapproach, in which key design variables are identified and appropriateranges of and relationships among these variables are determined withrespect to the effectiveness of the microbe-inhibiting character of theso-designed articles; and 2) a direct approach, in which the effectiveextent of the zone-of-inhibition is determined experimentally underconditions which simulate actual use of the article; and the appropriateranges of and relationship among design variables are thereby calculatedusing a mathematical model.

One means for determining whether a given design displays the desireddegree of microbe-inhibiting efficacy is as follows. Construct theamusement article according to the design; soak the article in a fluidcontaining microbes (e.g., tap water) for five minutes; transfer thearticle to the interior of an air-tight bag; heat at a desirableincubation temperature (e.g., 37° C.) for a desirable time (e.g., 8days); and have another person open the bag and grade the severity ofthe odor on a scale of 1 (bad) to 3 (no odor). An effective designproduces no noticeable odor.

It is necessary to determine several parameters of the components of thepet amusement article:

The volume of the cover or containment structure, V_(c). This is thetotal volume that can be held within the cover or containment structure.This can be determined as follows: fill the cover with small plasticbeads empty the beads into a large graduated cylinder or other containerfrom which one can read the volume and read the volume.

The densities of the fibers. It is necessary to know the fiber densitiesso that one can calculate the fiber volume from the fiber mass. If ahollow fiber is being used, it is usually advisable to use the effectiveof average or density.

The radius of the fibers, r_(f). The denier, which is the mass of afiber divided by its length, can be used to estimate the effective fiberradii, r_(f), as:$r_{f} = \sqrt{\frac{denier}{9{\pi \cdot 10^{5} \cdot \rho}}}$

where ρ is the average density (in units of gm/cm³) of the materialcomprising the fiber. If the fibers are roughly circular in crosssection, r_(f) should correspond closely to the average physical radiusof the fibers. If the fibers are decidedly non-circular incross-section, r_(f) is an effective averaged radius (i.e., the relevantbehavior is much as if the fibers were of circular cross-sectionalradius, r_(f)). The use of the above becomes increasingly accurate forfibers which are more circular in cross-section and which possess anarrower distribution in cross-sectional size. If the fibers are hollow,the proper equation is somewhat more complicated; but one can calculatethe radius using information supplied by the manufacturer.

After the above parameters are obtained, one can proceed to the designof the microbe-inhibiting article. There are several key variables thatmust be considered:

The volume fraction, x_(o), of initially microbe-inhibiting fiber. Thisis equal to the total volume of initially microbe-inhibiting fiber,VMI_(o), divided by the total volume of the containment structure, orx_(o,)=VMI_(o)/V_(c)

The average concentration of the microbe-inhibiting agent, C_(MI),within the initially microbe-inhibiting fiber.

The fiber blend volume fraction, ρ_(B). This is the volume fraction of acontainment structure that is comprised of fiber of any kind.

Then the following calculations can be made:

The fraction of the fiber blend that is composed of initiallymicrobe-inhibiting fiber, f_(MI): $f_{MI} = \frac{x_{o}}{\rho_{B}}$C_(B) = C_(MI)^(ρ_(B))f_(MI)

C_(MI) is used to calculate the average blend concentration, C_(B), as

C_(B) would be the concentration of the microbe-inhibiting agent in theentire blend if the agent were to diffuse and become completelyhomogeneous throughout the blend (i.e., it is the average concentrationof the microbe-inhibiting agent throughout the blend). If protectionthroughout the fiber blend is to be obtained, this value must be abovethe minimum efficacy level (sometimes referred to as a “minimuminhibitory concentration) for the particular microbe-inhibiting agentused.

Empirical Method

In designing effective microbe-inhibiting articles using a filling,where the filling possesses microbe-inhibiting properties, the designparameters of the fill must be chosen properly. The three key designvariables are x_(o), C_(MI), and ρ_(B). The variables x_(o) and f_(MI)must be sufficiently large that the initially microbe-inhibiting fibercan “spread” its inhibitory qualities throughout at least a predominantfraction of the entire blend, and preferably to the cover material aswell; but not so large that the cost becomes prohibitive. C_(MI) must besufficiently large that there is enough microbe-inhibiting agent in theinitially microbe-inhibiting fibers to spread to the initiallynon-microbe-inhibiting fibers (and optionally to the cover material) andstill maintain a concentration that exceeds the minimum inhibitoryconcentration. ρ_(B) must be sufficiently large that themicrobe-inhibiting efficacy can spread effectively throughout thearticle. If, for a given x_(o) and f_(MI), ρ_(B) is too small, thefibers will not be intermingled sufficiently, and the agent will not beable to diffuse effectively. If ρ_(B) is too large, the relative motionof the individual fibers will be severely restricted, and the spreadingof the microbe-inhibiting agent, which is facilitated by such motion,especially during vigorous use of the article, will be curtailed.

In determining the appropriate design parameters, the following designequation relates several of the key parameters:ρ_(B) C _(B) =C _(MI) x _(o)  (3)

It is generally necessary that C_(B) be much greater than the minimuminhibitory concentration. This is because, unless the agent is extremelymobile (which is not desirable due to durability concerns), the agentdoes not homogenize. For a considerable period of time, it retainsnotably higher concentrations near the source (initiallymicrobe-inhibiting) fibers. Thus, although C_(B) is the averageconcentration in the fiber assembly, much of the assembly will be at asignificantly lower concentration.

From tests using 2,4,4′-trichloro-2′-hydroxydiphenol, which isrepresentative of diffusing microbe-inhibiting agents, the followingdesign parameters were determined.

C_(B) should be greater than 0.001%; preferably greater than 0.01%; andmost preferably greater than 0.05%.

ρ_(B) should be between 0.1% and 15%; preferably between 0.6% and 10%;and

most preferably between 1% and 8%.

Once C_(B) and ρ_(B) are selected, the left-hand side of Eqn. (1) isdetermined; and C_(MI) and x_(o) are picked so that they are consistent.FIG. 4 shows x_(o) as a function of C_(MI) for several values of theρ_(B)C_(B)-product (in units of %²). For a particular desiredρ_(B)C_(B)-product, one can determine the appropriate x_(o) to use for agiven C_(MI) (or vice-versa).

It should be noted that C_(MI) cannot be arbitrarily large; it must bebelow a value at which the incorporation of the agent causessignificantly detrimental effects to the mechanical or chemicalstability or integrity of the fiber.

For a given C_(B), it is preferred that f_(MI) be as large as possible(its maximum value is one), i.e., C_(MI) be as low as possible. Forexample, it is preferable to have a fiber blend comprising 50% initiallymicrobe-inhibiting fiber with an agent concentration of 0.25% ratherthan a blend comprising 25% initially microbe-inhibiting fiber with anagent concentration of 0.5%. The larger f_(MI) is, the less one needs torely on diffusion of the microbe-inhibiting agents.

Zone-Of-Inhibition Method

This method requires estimating the effective extent(s) of thezone-of-inhibition, R_(ZI). It should be noted that the ranges of R_(ZI)are essentially phenomenological parameters. They are best measuredunder conditions similar to those present during use of the pet article.Means for conducting such measurements are given below.

In FIG. 3, the zone-of-inhibition 36 is represented by the region withinthe dashed lines surrounding the initially microbe-inhibiting fibers 34.It is seen that the zone 36 encompasses regions of the initiallynon-microbe-inhibiting fibers 32.

For larger materials, the zone of inhibition is often reported simply asa distance—without any reference to the size of the material. For finefibers, however, the effective zone of inhibition can diminish with thesize of the fiber. The physics of the zone of inhibition is complex, butits diminishment in finer fibers may be seen as due in part to thediminished capacity (defined as the total amount of agent that can leachfrom the fibers) of finer fibers. Values of the extent of the zone ofinhibition typically reported for large samples are generally notappropriate for fine fibers. Further, standard tests for the zone ofinhibition examine the extent of the inhibition into a relatively solidmaterial (e.g., agar gel). In a stuffed pet article, one is interestedin the zone of inhibition as it diffuses into the surrounding fibrousmedium.

When a fiber provided with a diffusing microbe-inhibiting agent iscombined with conventional fiber, it is generally desired that nearlyall the fibers be within the zones of inhibition of the initiallymicrobe-inhibiting fibers. One can obtain an estimate of the fraction ofthe entire blend, ζ, which is within a zone of inhibition by making ananalogy to the Formal Theory of Phase Transformations (e.g., see J. W.Christian, The Theory of Transformation in Metals and Alloys, PergamonPress, 1975). This theory describes the volume fraction of a materialthat has undergone a phase transformation.

If only a few initially microbe-inhibiting fibers are within aninitially non-microbe-inhibiting fiber assembly, the total volume withina zone of inhibition is given simply by adding up the volumes of thezones-of-inhibition of the few fibers. When there are sufficiently manyinitially microbe-inhibiting fibers that the zones-of-inhibition startto overlap—a situation desirable in the present invention—it isnecessary to “discount the excluded volume.” As a rule-of-thumb, forfibers (i.e., long and thin structures), the fraction of the entireblend, ζ, that is within a zone of inhibition can be estimated asζ≈1−exp(−(1α)² x _(o))  (4)

where $\begin{matrix}{\alpha = \frac{R_{ZI}}{r_{f}}} & (5)\end{matrix}$If ζ is close to unity, nearly all the conventional fiber is within thezones of inhibition of the initially microbe-inhibiting fiber.

For easy application to use with a wide variety of fibers, the effectiveextent of the zone of inhibition is represented by the dimensionlessparameter, α, which is equal to the ratio of the radial extent of thezone of inhibition, R_(ZI), to the effective radius of the fibers,r_(f).

The effective radial extent of the zone of inhibition, R_(ZI), can beestimated by a variety of means. A preferred means begins with thepreparation of a blend comprising the initially non-microbe-inhibitingfiber and a small amount (e.g., less than 1% by volume of the entireblend) of microbe-inhibiting fiber. The blend is then placed on a flatsurface and spread somewhat, trying to maintain as much as possible thepacking density of the fibers at a level comparable to that which isused in the end application. The entire sample is then inoculated with adesired test organism, and the sample is stored for a period of timenecessary for the organism to grow appreciably in areas which are notclose to microbe-inhibiting fiber (a control experiment, comprising onlynon-microbe-inhibiting fiber and the inoculating organisms, is performedsimultaneously). The sample is then viewed using a microscope, and theeffective range of inhibition is noted. Preferably, several measurementsshould be performed to ensure that one is measuring the range ofinhibition accurately. If the degree of microbial growth is insufficientat reasonably long experimental time scales, one can perform theexperiments with the fiber blend situated in contact with a knownnutrient material (e.g., agar), preferably immersed in the nutrientmaterial (e.g., place the fibers on an agar surface, inoculate, and thendeposit more agar on top). Alternatively, for the non-microbe-inhibitingfiber in the blend, one can use a fiber which is known to beparticularly susceptible to proliferation of the microbe(s) of interest.

R_(ZI)-values obtained by means described above will tend to beconservative, i.e., the “true” values may be somewhat larger. This isbecause use of the article generally involves mechanical stresses whichtend to spread the MI efficacy throughout the amusement article. Astatic measurement, such as that described above, neglects this.

Directly measuring R_(ZI) can be time-consuming; and the accuracy cansometimes be questionable. It is therefore sometimes preferable to treatR_(ZI) as a phenomenological parameter, i.e., to determine themicrobe-inhibiting efficacy on actual articles, and then to back-inferR_(ZI). The determined R_(ZI) can then be used for optimization of theactual design.

Eqn. (2) is more accurate when x_(o) is not too large (i.e., less thanabout 0.6). It also applies more straightforwardly in cases where thefibers are packed more densely. Furthermore, it is generally preferredthat, and the equation applies best when, the initiallymicrobe-inhibiting fiber is distributed homogeneously throughout thefiber blend. This can be brought about be mixing the blend well andoptionally by providing the fibers with anti-stick and/or anti-staticproperties.

FIG. 5 is a plot of ζ (the estimated volume fraction of the interior ofthe containment structure which is within a zone of inhibition) vs.x_(o) (in dimensionless units) for different values of α (also indimensionless units) x_(o) is the volume fraction of the interior of thecontainment structure which is comprised of initially microbe-inhibitingfiber; and α is the ratio of the effective radial extent of the zone ofinhibition to the effective fiber radius. Note that a log-scale is usedfor the x_(o)-axis.

Amusement articles for pets may also be made from containment structureswhich are filled with particulate filling materials, with foammaterials, or with combinations of these with fibrous materials. Forexample, one can use a particulate material which is provided withdiffusing microbe-inhibiting properties and combine it with conventionalnon-microbe-inhibiting fiber; or one can mix a foam material in whichhas been incorporated a microbe-inhibiting agent with a fibrousmaterial.

If the microbe-inhibiting filling material (or some fraction thereof) ismore particulate (i.e., three-dimensional) than fibrous, therule-of-thumb for calculating the fraction of the containment volumethat is within a zone of inhibition of the particulatemicrobe-inhibiting filling material isζ≈1−exp(−(1+α)³ x ₀)  (4)

where $\begin{matrix}{{\alpha = \frac{R_{ZI}}{r_{s}}}{and}} & (6) \\{x_{o} = \frac{{VMI}_{o}}{V_{c}}} & (7)\end{matrix}$

Here R_(ZI) is the effective radial extent of the zone of inhibition forthe microbe-inhibiting fibers used; r_(s) is the effective radius of themicrobe-inhibiting particles used; VMI_(o) is the volume ofmicrobe-inhibiting particles used in the blend; and V_(c) is the volumeof the interior of the filler containment structure (e.g., sewn fabricfor a stuffed pet toy).

If the particles are roughly spherical, r_(s) corresponds to theiraverage radius. If the particles are appreciably non-spherical, r_(s)should be interpreted as the effective average radius of the particles(i.e., the relevant behavior is much as if the particles were sphericalwith radius, r_(s)). Estimates of r_(s) can be obtained by variousmeans, including direct observation using a microscope. R_(ZI) andVMI_(o) can be obtained in manners similar to those used for fibers,discussed supra. Considerations similar to those for fibers, asdiscussed supra, apply with regard to the relationship between thefineness of the particles and the effective radial extent of their zonesof inhibition. V_(c) is obtained in the same manner as in the case wheremicrobe-inhibiting fibers are used, discussed supra.

In practice, the radius of the effective zone of inhibition willdiminish with time as the diffusing microbe-inhibiting agent isdepleted. The depletion rate is characteristic of the material and themicrobe-inhibiting agent used and it will increase with the packingdensity and the frequency and extent of washing and or abrasion.

It is preferred to construct microbe-inhibiting stuffed pet articlessuch that ζ is between about 0.5 and 1. It is more preferable toconstruct such articles such that ζ is between about 0.8 and 1. It ismost preferable to construct such articles such that ζ is between about0.9 and 1. It should be kept in mind that use of the article can spreadthe microbe-inhibiting efficacy; therefore, the effective ζ of anarticle may increase with use from its as-manufactured value.

Combinations can be used to create preferred articles for pets. Apreferred case is to blend conventional fiber with fiber containing adiffusing microbe-inhibiting agent and use the blend to fill acontainment structure whose outer surface has been treated with astrongly bonded microbe-inhibiting agent. Alternatively, one can alsouse the blend to fill a containment structure whose inner surface hasbeen coated with a latex compound in which a microbe-inhibiting agent isincorporated. The agent in this coating will diffuse to some degree.

Compaction Pre-Treatment of Fiber

As discussed earlier, when diffusing microbe-inhibiting agents are used,the diffusion of the agents from fibers that initially contained themicrobe-inhibiting agents to fibers that did not is an important aspectof the resulting microbe-inhibiting efficacy of the article. Thekinetics of this diffusion, in terms of distance that themicrobe-inhibiting agents diffuse, are governed by an effectivediffusion coefficient, D. To expose more fiber to the microbe-inhibitingagent in a given amount of time, one can maintain the fiber in acompacted state.

Markedly increased efficacy can thereby be obtained by maintaining thefiber in a compacted state for a period of time before using it asfilling for microbe-inhibiting articles of the present invention.Homogenization of the microbe-inhibiting agent occurs at a greatlyaccelerated rate when the fibers are so compacted; and toys fabricatedfrom such fiber will possess a relative uniformity of microbe-inhibitingagent concentration that is needed for efficacy in the demandingenvironment in which the toys are used.

The degrees of compaction should be such that the fiber is at a relativevolume fraction of greater than 10%, preferably greater than 14%, andmost preferably greater than 18%. Compaction should not be so strongthat the fiber is damaged (e.g., compaction levels greater than about40% may do more harm than good).

The desired compaction time is determined by the diffusivity of themicrobe-inhibiting agent from the initially microbe-inhibiting fiber tothe initially non-microbe-inhibiting fiber. One can perform diffusioncalculations appropriate for a porous medium to determine theappropriate times.

The “relative volume fraction” of the fiber is defined as the fractionof a given volume that is occupied by the fiber material. One way tocalculate this is as follows: Take the geometric volume occupied by thefiber (i.e., the volume the fiber appears to occupy); weigh the fiber inthis volume; from the known fiber effective density, calculate thevolume actually occupied by the fiber; divide this volume by thegeometric volume to obtain the volume fraction occupied by the fiber.(If the fiber is of the “hollow” type, allowances must be made.)Increasing the temperature will also increase the effective diffusioncoefficient; and if this process can be done cost effectively (which isoften a problem) and at a temperature that is below any degradationtemperature associated with the microbe-inhibiting agents, it can be auseful aid for homogenization.

Sample Uses of the Present Teaching

Empirical

Consider a stuffed pet toy with a containment volume of V_(c)=908 cm³that is to be made using a combination of a diffusing agentmicrobe-inhibiting triacetate fiber and a conventionalnon-microbe-inhibiting polyester fiber. The triacetate fiber has adensity, ρ, of about 1.32 gm/cm³; and the polyester fiber has a density,ρ, of about 1.39 gm/cm³. For a total blend density ρ_(B)=4%, and anaverage blend concentration of C_(B)=0.09%, the ρ_(B)C_(B)-product is0.36 (in units of %²), which is close to the value corresponding to theρ_(B)C_(B)=0.35 curve of FIG. 4. Suppose it is desired to usemicrobe-inhibiting fiber containing 0.3% of an agent similar to2,4,4′-trichloro-2′-hydroxydiphenol. Using FIG. 4, this corresponds toan x_(o)-value of about 1.2%. This corresponds to a volume of 10.9 cm³,or 14.4 gm of the triacetate fiber. The remaining 2.8% (or 25.4 cm³) ofthe fill volume is to be occupied by polyester fiber. This correspondsto about 35 gm of the polyester fiber. Thus, the appropriate blendcontains 35 gm of polyester fiber and 14.4 gm of triacetate fiberinserted into the 908 cm³ cover material.

Zone-Of-Inhibition

Consider a stuffed pet toy with a containment volume of V_(c)=350 cm³that is to be made using a combination of a diffusing agentmicrobe-inhibiting acrylic fiber having an approximately circularcross-section and a conventional non-microbe-inhibiting polyester fiber.The acrylic fiber has a density, ρ, of about 1.18 gm/cm³ and a denier of3. The effective radial extent of the zone of inhibition of the fiber ismeasured to be about 70 μm. The polyester fiber has a density, ρ, ofabout 1.39 gm/cm³.

A 3 denier fiber with density 1.18 gm/cm³ possesses an effective averageradius of about 6.7 μm. α for this system is therefore about 10.4. Thebehavior of this fiber will be close to that described by the “α=10”curve in FIG. 5. From the curve, it is seen that ζ approaches unity atx_(o)-values of about 4%-6%. This corresponds to a volume of about 14-21cm³ or a mass of about 17-25 gm. Therefore, to ensure that most of theinterior of the containment structure is within a zone of inhibition, itis necessary to include about 17-25 gm per toy of the microbe-inhibitingacrylic fiber. Assuming it is desired to for the containment structureto have a total filled volume of 10%, one must include a volume fractionof the polyester blend of about 6%-4%. The corresponds to a volume ofabout 21-14 cm³ or a mass of about 29-19 gm. The fibers should be wellblended together.

Generally, the denier of the fibers should preferably be between 0.8 and20, and most preferably between 1 and 15. The cut length of the fibershould preferably be between 0.1 inches and 8 inches, most preferablybetween 0.4 inches and 5 inches.

Manufacture of Microbe-Inhibiting Amusement Articles for Pets

Microbe-Inhibiting Fillers and Containment Structures

The manufacture of a textile-based stuffed pet toy typically begins withthe conversion of the textiles from roll form to the appropriate shapesand sizes via die-cutting. The shapes are usually complex, withirregular perimeters. These materials comprise the containment or covermaterial of the stuffed toy. For the case of a simple toy, the coverwill be formed from two halves cut from the textile.

The cut containment materials are then sewn around their perimeter, butnot closed; an aperture is left for subsequent stuffing of the toy. Thesize of the aperture is chosen to be compatible with the fillingapparatus and to allow for adequate containment of the stuffing for theperiod of time before the aperture is closed. For toys of typical sizesand for typical filling apparatuses, the aperture possesses a dimensionof about 0.5-2 inches. During the sewing process, the containmentmaterials can optionally be in an “inside-out” configuration so that theseam is concealed in the final product.

Microbe-inhibiting properties can be conferred to the toy by using afilling that is in whole or in part comprised of microbe-inhibitingmaterial by using a containment material which in whole or in partpossesses microbe-inhibiting properties, or by some combination of thetwo. The materials can be made microbe-inhibiting by suitably treatingthem, e.g., spraying with or soaking in a microbe-inhibiting solution,or by incorporating microbe-inhibiting agents during their manufacture.

The filling material is weighed, shredded, and blended (either manuallyor through a shredded/picker) and either hand-stuffed into the toy orblown into the toy using a blowing machine. After filling, the apertureis closed, e.g., by hand-sewing, machine-sewing, gluing, stapling, etc.

Another type of filling that can be used is comprised of a blend ofconventional polyester non-microbe-inhibiting fiber andmicrobe-inhibiting particulate matter in which the microbe-inhibitingproperties of the particulate are provided by incorporation of adiffusing microbe-inhibiting agent. The microbe-inhibiting particulatematter can be obtained in a variety of ways. For example, one can formpolystyrene beads incorporated with Microban microbe-inhibiting agent orproperty. One can also incorporate microbe-inhibiting agents intovarious zeolitic particulates. The zone of inhibition corresponding tothe particulate is essentially three-dimensional in character. Relativeto the fibrous (essentially two-dimensional) case, and to the extentthat α remains constant, a lesser volume fraction of the particles(x_(o)) is generally required for most of the containment material to bewithin a zone of inhibition. In this case, the relative compositionshould be such that the antimicrobial particulate comprises a volumefraction of the containment structure of more than about 1%, preferablymore than about 3%, and most preferably more than about 5%. Theremaining (non-microbe-inhibiting) fiber is added in an amount such thatthe fiber comprises between 0.1% and 15%; preferably between 0.6% and10%; and most preferably between 1% and 8% of the volume fraction of thetotal containment structure.

In the above case, however, the provision that a remains constant can bequite restrictive. This will generally require particulates withdiameters in the range of tens of microns. It will frequently beundesirable for such small particles to be free within the amusementarticle (they can escape from the containment structure and be breathedor otherwise taken up by the body of the pet or its owner). In practice,therefore, when beads or particles are used as part of a fill, they aremade to be larger (typically on a scale of millimeters). This sizeincrease causes α to become smaller, which reduces efficacy for a givenvolume fraction of material (see FIG. 1), but it provides for a saferand more attractive article; and one can simply increase x_(o) tocompensate.

Fillings in which the fiber has microbe-inhibiting properties and theparticulate does not can also be used. In this case, however, becausethe particulate is being used primarily for its filling properties (asopposed to microbe-inhibiting properties), there is no downside tomaking the particles larger. The effective diameter of the particulateshould be greater than about 0.50 mm, preferably greater than about 0.75mm, and most preferably greater than about 1.00 mm.

Shredded foam, polystyrene beads, polyester, and/or recycled or virginfiber can be substituted, in part or in whole, for conventional fiberand blended with antimicrobially-treated fiber as per the above. One canalternatively or in addition inject a microbe-inhibiting foam precursorinto the aperture and form the foam in-place.

Cut foam, all or in part microbe-inhibiting, can be used for filling ina variety of ways. For example, it can be cut to roughly the same sizeand shape as the cut halves and included in the interior of the articlebefore sewing; or short strips of foam can be obtained and used as afill in manners similar to that of fiber.

Microbe-inhibiting properties can be imparted to the containmentmaterial by spreading the rolls of the containment material and sprayingtheir surface(s) with a suitable microbe-inhibiting solution, e.g., asolution of an agent comprising a microbe-cidal quaternary ammoniumcompound functionality and a silane coupling agent functionality. Apreferred microbe-inhibiting agent of this type is Dow Corning 5700(active ingredient: 3-trimethoxysilylpropyl dimethyloctadecyl ammoniumchloride). If one is treating a porous material with a moderate-to-goodmoisture regain, and if purified water is the predominant solvent, theconcentration—as a percentage of the weight of the material beingtreated) should be approximately 0.01-1%. The preferred predominantsolvent is purified water; but other solvents, such as methanol andisopropanol can be used in conjunction with the purified water. Ifdesired, treatment can be carried out using a treatment bath rather thanby spraying. In either case, siloxane condensation catalysts can be usedto enhance condensation reactions and to induce a stronger bond of theagents to the surface of the material.

Attractive microbe-inhibiting amusement articles for pets can also bemade without using any fiber-filling. If a very high-pile cover material(made to be microbe-inhibiting by means discussed above) is used, thetoy may have an adequate feel for use, and the cost is reducedconsiderably relative to a toy containing fiber. One must ensure,however, that the entire cover is directly incorporated withmicrobe-inhibiting properties, or that a sufficient fraction of thefibers comprising the cover material were treated with a diffusing agentand that the agents has been effectively transferred to the otherfibers.

Microbe-Inhibiting Linings

Another means of imparting microbe-inhibiting properties to the toy isto utilize a microbe-inhibiting liner. This means can be used alone orin conjunction with the use of microbe-inhibiting filler and/orcontainment materials. For example, microbe-inhibiting flexible plasticsheets can be die-cut along with the containment material. These plasticsheets can then be placed on the backside (i.e., inner side) of thedie-cut containment materials before sewing. The subsequent sewingprocess will thereby incorporate a microbe-inhibiting plastic layer onthe inside of the containment material. The toys can then be filled inthe usual manner. Because the resulting containment structure can berelatively impermeable to air, if an air-driven filling machine is usedfor filling, it is useful to provide an extra aperture to allow for theair to escape. To avoid having to close another aperture in the finalstage of manufacture, however, it is generally preferable to use onlyone aperture and perform the filling in such a way that air can escapefrom the aperture through which filling is carried out.

Plastic linings are effective both because they can be treated withmicrobe-cidal agents and because they can be obtained relativelyimpermeable to microbes, liquids, dirt, dust, excrement, etc. Even ifthe linings do not possess microbe-cidal properties, they can stillpossess significant microbe-inhibiting properties by virtue of theirimpermeability to microbes and to material which encourages theproliferation of microbes.

Microbe-inhibiting vinyl sheet is a preferred material for the lining.The material can comprise a microbe-cidal treated vinyl sheet or it cancomprise a laminate structure with at least one layer comprising amicrobe-cidal treated plastic sheet. A difficulty with this type ofmaterial is that it tends to be somewhat stiff and the sewing processtends to require more dexterity and control, resulting in less efficientmanufacturing. To ameliorate this difficulty, softer, more pliableplastics are preferred. These can be obtained, e.g., by using thin vinylsheeting or increased concentrations of non-microbially-digestibleplasticizer in manufacturing the plastic. Alternatively, one can bondthe plastic sheet to the fabric. The bond can be weak (as via staticelectricity or a weak adhesive) or it can be strong (e.g., utilizing acoupling agent or an effective plastic-fabric adhesive).

A lining can be employed in the form of a bag inside the toy. Forexample, a containment structure for the toy can be constructed in theusual manner. A bag is then constructed by die-cutting two plastic cuthalves in approximately the same size and shape as the containmentmaterial. The appropriately shaped bag with an aperture can then beformed from the two plastic cut halves by placing one cut half on top ofthe other and applying heat to the perimeter. The bag is inserted intothe containment structure, the bag is filled with the filling materialwhile it is within the containment, and the aperture is sealed.

When a lining is used, filling can be facilitated by including in theshape of the lining a notch that protrudes from the aperture. Thenotches can help prevent fill from entering the space between the liningand the outer containment material.

A preferred means for incorporating a lining without increasing thedexterity and control required to attach the lining to the containmentmaterial is to employ a microbe-inhibiting soft fabric rather than amicrobe-inhibiting plastic sheet. Microbe-inhibiting cotton is apreferred material, as are polyester/cotton blends and acrylic-basedfabrics. These fabrics are generally permeable to microbes, liquids,dirt, dust, excrement, etc., and hence do not possess themicrobe-impenetrable characteristics of the plastic sheeting used.

Rather than using a separate lining material, one can apply a coating ofmicrobe-inhibiting plastic to the backside of the fabric comprising thecontainment material. It is preferred to use a latex suspension to whicha microbe-inhibiting agent has been added. The resulting suspension canbe applied to the backside of the containment material using, e.g., abrush or a roller. The resulting latex coating provides microbe-cidalprotection due to the incorporated microbe-cidal agent;microbe-impenetrable protection (if the coating is continuous across thefabric); and desirable physical characteristics such as increaseddimensional stability, increased durability, and increased resilience.It can also facilitate cutting operations. Such latex coatings areparticularly efficacious because they can be applied so that theresulting fabrics do not have an excessively stiff feel. Polyurethanecoatings with added microbe-inhibiting agents are also preferred.

Non-Woven Articles

A unique type of amusement article for a pet is composed primarily froman extremely high-loft non-woven material structure, such as those usedin filtration systems. The high-loft, low density material can beprepared by known techniques (e.g., from extruded continuous filamentsor from fiber webs or batts strengthened by bonding between or amongfibers). The fiber bonding can be brought about by heating (includingthe use of low-melting coatings), by using adhesives, stitch-bonding, ormechanical interlocking (e.g., needling). The material can then bedie-cut into desired shapes (e.g., fish, mouse, star, cloud, disc, bone,bear, etc).

If the fibers comprising the non-woven structure are very well-bonded toeach other, the die-cut toy can be used as is. If they are notsufficiently well-bonded, one can seal the outer perimeter of the toysby some other means (e.g., local heating, stitching, serging, tacking,etc.).

These toys can be made microbe-inhibiting by use of microbe-inhibitingfibers or fiber blends, where the fibers are incorporated with amicrobe-inhibiting agent at the time of their manufacture orpost-treated with a microbe-inhibiting agent. If an agent of thediffusing type is used, only a fraction of the fibers is required to beinitially microbe-inhibiting (the magnitude of this fraction isdetermined in the same manner as for the fiber-fill). If the agent is ofthe strongly bonded type, it is preferred that most (if not all) of thefiber be initially microbe-inhibiting. Preferred base materials arepolyester or olefin fibers or filaments.

It is important to ensure that procedures used commonly in non-wovenmanufacture (e.g., heat-bonding, application of adhesives, etc.) doesnot diminish the microbe-inhibiting efficacy of the finished product.For example, heat-bonding must be done at a temperature lower than thedegradation temperature of the microbe-inhibiting agents used. Adhesivesor low-melt outer coatings must not block the diffusion ofmicrobe-inhibiting agents (in the diffusing agent case) or overcoat themicrobe-inhibiting surface (in the strongly-bonded agent case).

In cases where the adhesive or other coatings only need to be applied toa fraction of the fibers or filaments and the microbe-inhibiting agentsonly need to be incorporated into a fraction of the fibers or filaments,it is preferred that these fractions be separate. It cases where this isnot advisable (e.g., the fiber fraction which needs to be incorporatedwith a microbe-inhibiting agent is too large, or a strongly bonded agentis being used), it is preferred to post-treat the high-loft batting whenit is in roll form (i.e., after it is already bonded), using a bath orspray technique.

A particularly preferred non-woven material for the present invention isa very high-loft low density type such as those used in filtrationsystems. The materials can be purchased from a filter manufacturer inroll form and then post-treated or can be incorporated in the fibersthat comprise the filter.

The desired thickness of the non-woven material for these articles willvary with the lateral size of the article, the type of perimeter bondingused, and with consumer preference. When perimeter bonding is broughtabout by sewing the perimeter, and the lateral size of the article isrelatively small (e.g., shortest dimension on the order of several timesthe thickness), the sewing tends to decrease dramatically the averagethickness of the articles, and the starting material should therefore beseveral times thicker than the desired final thickness. Generally,desired average thickness of the finished toys is on the order of inches(about 0.5-4 inches).

Odor-Control

Pet toys often have a tendency to emit odors. There are numerous causesfor such odors, many of which are related to microbes. It is thereforean additional benefit to the use of pet articles possessingmicrobe-inhibiting properties that such articles will frequently displaya reduced tendency to develop odors.

A wide variety of anti-odor (or deodorizing) compositions are known inthe art. Odor masking, the intentional concealment of one odor byanother odor, is perhaps the most common means for controlling odors.Odor masking on fabrics can be accomplished using various perfumes,colognes, etc. Relatively high levels of the masking agent are oftenrequired for adequate concealment of the odor.

Odor modification, where the odor is changed, as by chemicalmodification, can also been used; and it is frequently preferred overodor masking. The odor can be modified to become less offensive or canbe diminished or neutralized.

In many cases it is preferred to use an odor-absorbing material ratherthan a masking or modification agent. Odor absorbing materials are often“broad spectrum” in nature, i.e., they are effective in neutralizingmany different odor-causing agents. Common odor absorbing materialsinclude activated charcoal and zeolites. These materials are typicallyused in a particulate form. They can be incorporated into the petarticle in a variety of ways, as directly into the materials comprisingthe article during their manufacture; or added to some component of thearticle during its manufacture; or adhered to some component(s) of thearticle.

A further advantage of microbe-inhibiting pet toys of the presentinvention is that, if it is desired to incorporate deodorizing,odor-modifying, or odor-masking materials, less such materials areneeded than in a comparable article which did not possessmicrobe-inhibiting properties.

A preferred class of zeolites for use as odor absorbents are theintermediate silicate/aluminate zeolites. The intermediate zeolites canbe characterized as having silica/alumina molar ratios of less thanabout 10. With regard to the present invention, intermediate zeolitesare often preferred over “high” zeolites. The intermediate zeolitespossess a higher affinity for amine-type odors; they are generally moreefficient in odor absorption because they typically have larger surfaceareas; they are generally more moisture tolerant; and they retain moreof their odor absorbing capacity in water than do “high” zeolites.

Carbonaceous materials that serve effectively as absorbents for organicmolecules are often referred to as activated carbon or activatedcharcoal. Many of these materials are suitable for use in the presentinvention. They are available from commercial sources under such tradenames as Calgon-Type CPG, Type PCB, Type SGL, Type Cal, and Type OL.

IN SUPPORT OF THE PRESENT INVENTION THE FOLLOWING EXPERIMENTS WERECONDUCTED Examples Example No. 1

A 1000 cm³ cover structure in the shape of a disc is to be filled with afiber blend; and the total blend is to comprise 3.75% of the totalcontainment volume. The average blend concentration of themicrobe-inhibiting agent is to be greater than 0.14%. A triacetate fiber(density=1.32 gm/cm³) in which was incorporated 0.5% triclosanantimicrobial agent during its manufacture, as well as conventionalpolyester fiber (density=1.39 gm/cm³) are to be used.

The filling is prepared using the design equations (1)-(6) set forthabove. It is necessary to have the microbe-inhibiting triacetate fiberoccupy a volume fraction of the containment structure equal to about1.1%, and to have the conventional polyester fiber occupy a volumefraction of the containment structure equal to about 2.6%. 14.8 gm ofthe microbe-inhibiting triacetate fiber (possessing a denier of about 6and cut to a length of about 2″) was therefore blended with 36.5 gm ofconventional polyester fiber (possessing a denier of about 6 and cut toa length of about 2″). In this case, the average blend concentration,C_(B), is about 0.15%.

Example No. 2

A 500 cm³ cover structure in the shape of a bone is to be filled with afiber blend; and the total blend is to comprise 2.8% of the totalcontainment volume. The average blend concentration of themicrobe-inhibiting agent is to be greater than 0.38%. An acrylic fiber(density=1.18 gm/cm³) in which was incorporated 0.65% triclosanantimicrobial agent during its manufacture, as well as conventionalnylon fiber (density=1.14 gm/cm³) are to be used.

The filling is prepared using the design equations (1)-(6) set forthabove. It is necessary to have the microbe-inhibiting acrylic fiberoccupy a volume fraction of the containment structure equal to about1.7%, and to have the conventional nylon fiber occupy a volume fractionof the containment structure equal to about 1.1%. 9.9 gm of themicrobe-inhibiting acrylic triacetate fiber (possessing a denier ofabout 3.5 and cut to a length of about 1.5″) was therefore blended with6.4 gm of conventional nylon fiber (possessing a denier of about 5.5)and cut to a length of about 1.5″). In this case, the average blendconcentration, C_(B), is about 0.39%.

Example No. 3

A 2000 cm³ cover structure in the shape of a bear is to be filled with afiber blend; and the total blend is to comprise 4% of the totalcontainment volume. The average blend concentration of themicrobe-inhibiting agent is to be about 0.1%. A polypropylene fiber(density=0.93 gm/cm³) in which was incorporated 0.2% Tri-n-butyltinmaleate (Ultra Fresh DM-50) antimicrobial agent during its manufacture,as well as regular polyester fiber (density=1.39 gm/cm³) are used.

Using the design equations (1)-(6) set forth above, it is necessary tohave the microbe-inhibiting polypropylene fiber occupy a volume fractionof the containment structure equal to about 2.2%, and to have theconventional polyester fiber occupy a volume fraction of the containmentstructure equal to about 1.8%. 40.9 gm of the microbe-inhibiting fiber(possessing a denier of about 4 and cut to a length of about 2″) wastherefore blended with 50.0 gm of conventional polyester (with a denierof 5 and cut to a length of about 2″).

Example No. 4

The cover or containment material was constructed from syntheticlambswool, also known as “fleece,” or shearling. The material has twosides: a fleece side, which simulates the fleece of a lamb; and abacking or back-side. The synthetic lambswool may be obtained fromTex-Tenn Corp., (Gray, Tenn.). It is comprised primarily of polyester,but is blended with a small amount of acrylic. The material has a weightof 17.5 oz/linear yard and is obtained on 60″-wide rolls.

Four rolls are suspended on a rack, and the synthetic lambswool ispulled from the rolls in tandem and fed onto the bed of the die-cuttingpress. A steel-rule die in the shape of a bone (long dimension about 7″)is placed on top of the layers of synthetic lambswool and beneath thehead of the die press. The head of the die press is then brought downonto the steel-rule die, whereupon it cuts through the four layers offabric in a single strike to yield four pieces of bone-shaped syntheticlambswool. The pieces are referred to as “cut halves.”

Two cut halves are then placed together such that the fleece sides arefacing each other. The two cut halves are then sewn together along theirmutual perimeter, leaving a 1-2″-wide orifice for later insertion of thefilling. The sewn material is then flipped inside-out such that thefleece side was on the exterior. The volume of the bone-shapedcontainment structure is obtained by filling a nominally identicalunfilled containment structure with small, plastic beads andsubsequently transferring the beads to a large graduated cylinder. Thevolume is readily obtained from the markings on the graduated cylinder.The volume of the containment thereby obtained is about 900 cm³. Themass of the cover structure is about 20.7 gm.

It is desired to fill the toy to a volume fraction of about 3.5%.

The microbe-inhibiting fiber used is acrylic. The fibers aresolution-spun, and triclosan is added to the spin dope to produce fiberscontaining about 0.2% triclosan. The fiber is cut to a length of 1″, andis blended with conventional acrylic fiber, which is also solution-spunand cut to a length of about 1″. Both fibers possess a denier of about3.5. The average blend concentration, C_(B), equal to about 0.08%.

From the design equations (1)-(6) set forth above, it is determined thatit was necessary to have the microbe-inhibiting acrylic fiber occupy avolume fraction of the containment structure equal to about 1.4%, and tohave the conventional acrylic fiber occupy a volume fraction of thecontainment structure equal to about 2.1%. 14.9 gm of themicrobe-inhibiting acrylic fiber is therefore blended with 22.3 gm ofconventional acrylic fiber.

The fill is then inserted through the aperture of the cover structure,and the aperture is then sewn closed. A stuffed dog toy in the shape ofa bone, where the filling is provided with microbe-inhibitingproperties, is thus obtained.

Example No. 5

Bone-shaped fleece-type toys are constructed in the same manner and withthe same dimensions as in Example No. 4, except that the filling isincorporated into the toy using a blowing/filling machine. It is desiredto fill about 200 toys. The calculations in Example No. 4 are scaled-upby a factor of 200. About 3.0 kg of the microbe-inhibiting acrylic fiberare therefore blended with about 4.5 kg of conventional acrylic fiber.The material is placed in the hopper of the blowing/filling machine.About 37.2 gm of the fiber blend is blown into the cover structure(There is a measuring scale near the operator of the blowing/fillingmachine; the toy periodically placed on the scale; and since the coverweighs 20.7 gm, each toy is filled until its mass is about 57.9 gm.Operators soon become sufficiently skilled than frequent measuring isnot necessary).

The aperture is then sewn closed. Stuffed dog toys in the shape ofbones, where the filling is provided with microbe-inhibiting properties,are thus obtained.

Example No. 6

The material comprising the containment structure of the toy is providedwith microbe-inhibiting properties by virtue of a topical treatment. Thetreatment is carried out before the shapes are cut with the die press. Aroll of the synthetic lambswool is unrolled and taken up onto aninitially empty roll. While the fabric is in the unrolled state betweenthe two rolls, it is sprayed with a microbe-cidal solution on the fleeceside.

The solution is obtained by mixing 5 oz. of Quat EPA 12 with 1 gallon ofpurified water. (The active ingredient of Quat EPA 12 is the quaternaryammonium compound, alkyl dimethyl benzyl ammonium chloride.)

After the synthetic lambswool is treated, it is used in the mannerdescribed in Example No. 4 to construct a bone-shaped containmentstructure. It is desired to fill the cover material only withnon-microbe-inhibiting fiber, and to fill it to a volume fraction ofabout 3.5%. The containment structure is filled with about 43.8 gm ofconventional polyester fiber. A stuffed dog toy in the shape of a boneand possessing microbe-inhibiting properties is thus obtained.

Example No. 7

The toy is provided with microbe-inhibiting properties by incorporatinga liner. Artificial lambswool and white Staph-Chek Microvent Comfortfabric (a textile backed thermoplastic film sold by Herculite Products,Inc.) are die-cut using a bear-shaped die (about 7″ on the longdimension). As in Example No. 4, the two cut halves of the artificiallambswool are placed with their fleece sides facing one another (theback-sides facing outward). The cut halves of the Staph-Chek MicroventComfort fabric are then placed directly in contact with the twobacksides. The four-layer composite is then sewn and inverted as inExample No. 4, resulting in a bear-shaped containment structure with amicrobe-inhibiting liner.

It is desired to fill the cover material only withnon-microbe-inhibiting polyester fiber, and to fill it to a volumefraction of about 3.5%.

The volume of the bear-shaped cover structure is obtained by filling anominally identical unfilled containment structure with small, plasticbeads and subsequently transferring the beads to a large graduatedcylinder. The volume is readily obtained from the markings on thegraduated cylinder. The volume of the containment thereby obtained isabout 1240 cm³.

It is desired to fill the toy to a volume fraction of about 3.5%. Thecontainment structure is therefore filled with about 60.3 gm ofconventional polyester fiber. A stuffed pet toy in the shape of a bearand possessing microbe-inhibiting properties is thus obtained.

Example No. 8

The toy is provided with microbe-inhibiting properties by incorporatinga microbe-cidal liner. They toy is constructed in the same manner andwith the same dimensions as in Example No. 7, except that the linermaterial is die cut from sheets of Aegis High Density (tight-weaveantibacterial fabric available from Precision Fabrics Group, Inc.).

Example No. 9

The toy is provided with microbe-inhibiting properties by incorporatinga microbe-cidal liner. They toy is constructed in the same manner andwith the same dimensions as in Example No. 7, except that the linermaterial is die cut from sheets of Staph-Chek Synergy fabric (Asynthetic textile fabric with a thermoplastic backing and amicrobe-cidal agent in the adhesive between the fabric and the backingsold by Herculite Products, Inc.).

Example No. 10

The toy is hereby provided with microbe-inhibiting properties byincorporating a microbe-cidal liner. They toy is constructed in the samemanner and with the same dimensions as in Example No. 7, except that theliner material is die cut from sheets of Staph-Chek Microvent Softfabric (A non-woven textile with a thermoplastic backing and containingmicrobe-cidal properties sold by Herculite Products, Inc.).

Example No. 11

The toy is hereby provided with microbe-inhibiting properties byincorporating both a microbe-cidal liner and microbe-cidal fill. Theytoy is constructed in the same manner and with the same dimensions as inExample No. 8, except that in the present example, a microbe-inhibitingfiber blend is used. All of the fiber is acrylic. The fibers aresolution-spun, and triclosan is added to the spin dope to produce fiberscontaining about 0.5% triclosan. The fiber is cut to a length of 1″. Itis blended with conventional acrylic fiber, which is also solution-spunand cut to a length of about 1″. Both fibers possess a denier of about3.5. It is desired to have a total fill volume fraction of about 3.5%,and an average blend concentration, C_(B), equal to about 0.1%.

From the design equations (1)-(6) set forth above, it is determined thatit was necessary to have the microbe-inhibiting acrylic fiber occupy avolume fraction of the containment structure equal to about 0.7%, and tohave the conventional acrylic fiber occupy a volume fraction of thecontainment structure equal to about 2.8%. 10.2 gm of themicrobe-inhibiting acrylic fiber is therefore blended with 40.0 gm ofconventional acrylic fiber.

The fill is then inserted through the aperture of the cover structure,and the aperture is then sewn closed. A stuffed dog toy in the shape ofa bear, where the filling is provided with microbe-inhibitingproperties, is thus obtained.

Example No. 12

A roll of Polyfill Extra-Loft Antibacterial Batting (a non-wovenpolyester treated with Dow Corning 5700 antimicrobial agent, availablefrom Fairfield Processing Corporation) is spread out on a cutting table.Seven rolls are suspended on a rack, and the material is pulled from therolls in tandem and fed onto the bed of the die-cutting press. Asteel-rule die in the shape of a mouse (long dimension about 4″) isplaced on top of the layers of the material and beneath the head of thedie press. The head of the die press is then brought down onto thesteel-rule die, whereupon it cuts through the seven layers of fabric ina single strike to yield seven pieces of mouse-shaped non-wovenmaterial. The mutual outer perimeter of the seven-layer structure isthen serged on a serging machine. This serves as an attractive pet toy,particularly for cats without any edge treatment.

Example No. 13

A 1.5″ non-woven filter composed of blue polyester fibers (from NationalFilter Media Corporation) is obtained in roll form. Two rolls aresuspended on a rack, and the material is pulled from the rolls in tandemand fed onto the bed of the die-cutting press. A steel-rule die in theshape of a mouse (long dimension about 4″) is placed on top of thelayers of the material and beneath the head of the die press. The headof the die press is then brought down onto the steel-rule die, whereuponit cuts through the two layers of fabric in a single strike to yield twomouse-shaped toys. These toys serves as attractive pet toys,particularly for cats.

Example No. 14

A high-loft non-woven batting material composed of 15% cellulose acetatefiber and 85% polyester fiber, in which the cellulose acetate fiber hasbeen incorporated with Microban antimicrobial agent at the time ofmanufacture of the fiber, is obtained in roll form (Carpenter Company).The material has a thickness on the order of 0.5″. 8 layers of thematerial are placed onto the bed of a die-cutting press. A steel-ruledie in the shape of a cloud (long dimension about 5″) is placed on topof the layers of the material and beneath the head of the die press. Thehead of the die press is then brought down onto the steel-rule die,whereupon it cuts through the eight layers of fabric in a single striketo yield eight pieces of cloud-shaped non-woven material. After ensuringthat the eight pieces are aligned, the outer perimeter is serged on aserging machine. The resulting toy is especially attractive for cats.

Example No. 15

A polypropylene particulate is prepared containing about 0.2% Triclosan.An amount necessary to fill a cover structure to a volume fraction ofabout 35% is placed into a mesh bag, which is then sewn shut. A pair ofcut halves are prepared. Before sewing, however, part of the edge of themesh bag is aligned with part of the edge of one of the cut halves. Thecut halves are then sewn in the usual manner, leaving an aperture largeenough for the sewn cover/mesh bag combination to be inverted. Afterinversion, the aperture is sewn shut.

Example No. 16

A bone-shaped cover structure is made in the same manner and with thesame dimensions as in Example No. 4. The cover structure is then filledwith a well-mixed blend of 38 gm of acrylic fiber (incorporated with0.2% triclosan; denier=3.5; cut length=1″) and 65 gm of Poly-Pellets(polypropylene beads, available from Fairfield Processing Corporation).The aperture of the filled cover structure is then sewn closed.

Example No. 17

The cover or containment material was constructed from Aegis HighDensity fabric (a tight-weave antibacterial fabric available fromPrecision Fabrics Group, Inc.). Four rolls are suspended on a rack, andthe fabric is pulled from the rolls in tandem and fed onto the bed ofthe die-cutting press. The same die as in Example No. 4 is placed on topof the layers of the fabric and beneath the head of the die press. Thehead of the die press is then brought down onto the steel-rule die,whereupon it cuts through the four layers of fabric in a single striketo yield four pieces of bone-shaped fabric. The pieces are referred toas “cut halves.”

Two cut halves are then placed together such that they are superimposed.The two cut halves are then sewn together along their mutual perimeter,leaving a 1.5″-wide orifice for later insertion of a filling. The sewnmaterial is then flipped inside-out such that the sewing cannot be seen.

The toy is to be filled to a volume fraction of about 3.5%.

The microbe-inhibiting fiber used is acrylic. The fibers aresolution-spun, and triclosan is added to the spin dope to produce fiberscontaining about 0.2% triclosan. The fiber is cut to a length of 1″, andis blended with conventional acrylic fiber, which is also solution-spunand cut to a length of about 1″. Both fibers possess a denier of about3.5. The average blend concentration, C_(B), equal to about 0.08%.

From the design equations (1)-(6) set forth above, it is determined thatit was necessary to have the microbe-inhibiting acrylic fiber occupy avolume fraction of the containment structure equal to about 1.4%, and tohave the conventional acrylic fiber occupy a volume fraction of thecontainment structure equal to about 2.1%. 14.9 gm of themicrobe-inhibiting acrylic fiber is therefore blended with 22.3 gm ofconventional acrylic fiber.

The fill is then inserted through the aperture of the cover structure,and the aperture is then sewn closed. A stuffed dog toy in the shape ofa bone, where the filling is provided with microbe-inhibitingproperties, is thus obtained.

Example No. 18

A bone-shaped toy is made in the same manner, with the same dimensions,and with the same filling as in Example No. 17; but the cover structureis instead made from rolls of Staph-Chek Synergy fabric (HerculiteProducts, Inc.).

Example No. 19

The cover or containment material was constructed from light nylonfabric. Eight rolls are suspended on a rack, and the fabric is pulledfrom the rolls in tandem and fed onto the bed of the die-cutting press.A steel-rule die in the shape of a fish (long dimension about 5″) isplaced on top of the layers of nylon and beneath the head of the diepress. The head of the die press is then brought down onto thesteel-rule die, whereupon it cuts through the eight layers of fabric ina single strike to yield eight pieces of fish-shaped nylon fabric. Thepieces are referred to as “cut halves.”

Two cut halves are then placed together such that they are superimposed.The two cut halves are then sewn together along their mutual perimeter,leaving a 1.5″-wide orifice for later insertion of a filling. The sewnmaterial is then turned inside-out such that the sewing cannot be seen.Polyurethane foam which has been incorporated with Ultra-Fresh DM-50antimicrobial agent (Carpenter Company) is die-cut into small (2 cm×2cm×2 cm) cubes. About fifty of these cubes are inserted into the nyloncover structure; and the aperture is then sewn closed.

Example No. 20

The cover or containment structure is made from a denim fabric. Eightrolls are suspended on a rack, and the fabric is pulled from the rollsin tandem and fed onto the bed of the die-cutting press. The same die asused in Example No. 4 is placed on top of the layers of denim andbeneath the head of the die press. The head of the die press is thenbrought down onto the steel-rule die, whereupon it cuts through theeight layers of denim in a single strike to yield eight pieces ofbone-shaped denim fabric. The pieces are referred to as “cut halves.”

Two cut halves are then placed together such that they are superimposed.The two cut halves are then sewn together along their mutual perimeter,leaving a 1.5″-wide orifice for later insertion of a filling. The sewnmaterial is then flipped inside-out such that the sewing cannot be seen.The structure is to be filled to a volume density of 3.2%. About 40 gmof Polyfill antibacterial fiber fill (100% polyester fiber treated withAegis Microbe-Shield; available from Fairfield) is inserted through theaperture, which is then sewn closed.

While particular embodiments of the invention have been shown, it willbe understood, of course, that the invention is not limited theretosince modifications can be made by those skilled in the art,particularly in light of the foregoing teachings. Reasonable variationand modifications are possible within the scope of the foregoingdisclosure of the invention without departing from the spirit of theinvention.

1. An amusement article to be played with or retrieved by, or forenticing a domestic animal comprising: a unitary piece of non-wovenmaterial defining a shape in the form of a small article for luring orbeing fetched by the domestic animal; and an effective amount of amicrobe-inhibiting agent applied to or incorporated within at least aportion of said unitary piece of material.
 2. An amusement articleaccording to claim 1 wherein the article is in the form of one of ananimal, a bone, a heart, and a geometric shape.
 3. An amusement articleaccording to claim 2 wherein the non-woven material comprises a fibrousbatting selected from the group consisting of polyolefin, acrylic,nylon, polyester, polyurethane, polyethylene terephthalate, celluloseacetate, triacetate resin fibers and blends thereof.
 4. An amusementarticle according to claim 3 wherein the microbe-inhibiting agent ispresent from 0.001 to 10 percent by weight of the unitary piece ofmaterial.
 5. An amusement article according to claim 1 wherein thenon-woven material comprising a high loft, low-density fibrous materialwhich is held together by bonding the fibers together.
 6. An amusementarticle according to claim 5 wherein the fibers comprise alow-temperature coating or sheath and the bonding takes place by heatingthe fibers to melt the coating or sheath and melt-bond the fiberstogether
 7. An amusement article according to claim 5 wherein the fibersare adhesively bonded together.
 8. An amusement article according toclaim 1 wherein the unitary piece of non-woven material has an outerperimeter and the non-woven material is sealed at the outer perimeter.9. An amusement article according to claim 8 wherein the non-wovenmaterial is sealed at the perimeter by local heating, stitching, sergingor tacking.
 10. An amusement article according to claim 1 wherein themicrobe-inhibiting agent is a compound selected from at least one of thegroup consisting of heavy metal salts, halogenated dioxides, quaternaryammonium compounds, halogenated compounds, sulfur compounds, phenylderivatives, phenoxy derivatives, thiazoles, chlorinated phenoliccompounds, polysubstituted imine salts and phosphate esters, andmixtures thereof.
 11. An amusement article according to claim 1 whereinthe microbe-inhibiting agent is selected from the group consisting ofchlorine dioxide and 2,4,4′-trichloro-2′-hydroxydiphenyl.
 12. Anamusement article according to claim 11 wherein the microbe-inhibitingagent is 2,4,4′-trichloro-2′-hydroxydiphenyl which is incorporated intoat least a portion of resin fibers.
 13. An amusement article accordingto claim 12 wherein the fibers comprise acrylic fibers and the2,4,4′-trichloro-2′-hydroxydiphenyl compound is incorporated into atleast some of the acrylic fibers.
 14. An amusement article according toclaim 1 wherein the microbe-inhibiting agent is bonded to at least aportion of the fibers.
 15. An amusement article according to claim 1wherein the microbe-inhibiting agent exhibits a zone of influence whichextends beyond the portion of the fibers on which the microbe-inhibitingagent or property is incorporated.